Unjust Enrichment

Editorial Committee of the Cambridge Law Journal

Unjust EnrichmentAuthor(s): Steve HedleySource: The Cambridge Law Journal, Vol. 54, No. 3 (Nov., 1995), pp. 578-599Published by: Cambridge University Press on behalf of Editorial Committee of the Cambridge LawJournalStable URL: http://www.jstor.org/stable/4508129 .

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Cambridge Law Journal. 54(3), November 1995, pp. 578-599 Printed in Great Britain

"UNJUST ENRICHMENT"

STEVE HEDLEY*

RESTITUTION has always been part of the common law. Yet in recent

years a startling transformation has taken place: an active and determined group of scholars have collected together the hitherto scattered materials, insisting that this is the only way in which these materials can be understood; and have claimed that despite the apparent diversity they are all bound together by a single notion, that of "unjust enrichment". A great deal of attention has been paid to elaborating this notion, and to defending particular conceptions of it.

My argument here is that this emphasis on the theory of "unjust enrichment" has gone much too far. The benefits to be expected from a rigid definition were always small; the costs are obvious enough, not least in the academic time spent arguing rival conceptions; and the result is a straightjacket which cannot accommodate all the various species of liability. In short, while there is nothing very obviously wrong with defining restitutionary claims as being "based on unjust enrichment", attempts to give any more precise meaning to "unjust enrichment", or the elements which are said to comprise it, have so far proved detrimental.

I refer throughout, stipulatively, to "unjust enrichment theorists", by which I mean those who continue to use this theoretical understanding of the subject, or even to develop it further. My targets are the key. theoretical notions used by these theorists: the various conceptions of "injustice" and of the "unjust factors" into which it is resolved; theories on the meaning of "enrichment" and the valuation of benefits; and the various varieties of the claim that restitution, or parts of it, are "independent" of other legal categories. I am not concerned to make a general case against the theory, which has already been done,' but rather to examine and evaluate the ways in which these concepts have in fact been used in the past decade. Moreover, I am not engaged in a crusade against "theory" in general, beyond insisting that any worth-

* Fellow of Christ's College, Cambridge. I am grateful to Professor Jack Beatson for comments on an earlier draft. On attempts to divide restitution off from other areas, see S. Hedley, "Contract, Tort and Restitution; or, On Cutting the Law Down to Size" (1988) 8 L.S. 147; on the use of the theory within restitution, see S. Hedley, "Unjust Enrichment as the Basis of Restitution" (1985) 5 L.S. 56.

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while theory ought to be able to show credentials of usefulness, by helping to solve the problems it addresses. These theoretical conceptions, as I hope to show, fail this test.

More positively, I hope to show that the excellent work that has been done on the development of the law and on possible reforms- much of it by the very same "unjust enrichment" theorists-is all the better when it ignores "unjust enrichment" theory. The burgeoning law of restitution does not need this crutch, and would be much improved by casting it away. Whether restitution is worthy of study is an entirely separate question from what theoretical apparatus is necessary for expounding it; but perhaps a certain level of self- confidence is required before this truth sinks in, and it is more clearly seen that doubts about the appropriate level for theory are far removed from doubts whether restitution should be studied at all.

My complaint is against particular theories, not particular theorists, but I must say a few words on the relation between the two. The principal architect of moder "unjust enrichment" theory is of course Birks, and its first full exposition his Introduction to the Law of Restitution.2 On its publication, a significant number of restitution scholars almost immediately began to express their ideas within this theoretical framework; particularly instrumental in popularising the theory was Burrows' The Law of Restitution.3 I am acutely aware of differences of approach between theorists, and that there are important current writers such as Jones, Beatson and Tettenborn who have expressed only limited enthusiasm for the theory, and are each, in their different ways, dissenters from it. Yet no contemporary scholar would dispute that there is a distinct "unjust enrichment" theory with a wide following, however much its followers may argue over the details.

Developments in restitution in the last decade have been rapid indeed, both in the academic sphere and in the judicial, and I will start with the latter, where Burrows claims that "a coherent and principled" approach is now prevalent, with "any argument to the contrary ... authoritatively silenced" by the cases.4 Yet very far from accepting "unjust enrichment" theory, I argue, the judiciary have so far shown little awareness of it, and even less liking. What we see falls far short of acceptance: it is much more limited, and considerably more complex.

2 (Oxford 1985) (hereafter Birks, Introduction). (London 1993) (hereafter Burrows, Restitution).

4 Burrows, Restitution, p. vii.

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The Cambridge Law Journal

THE JUDICIAL REACTION

The acceptance of "unjust enrichment" by the judiciary is limited to this: that a considerable number of judges now recognise that there is an important subject called "restitution", and that in general terms it concerns the removal of benefits that would otherwise unjustly enrich the defendant. A search for the words "unjust enrichment" and related expressions in recent cases5 shows that there are now between 15-20 cases a year where judges use these expressions.6 (To keep some kind of perspective, the equivalent figure for "contract" would be 1,200 per year,7 "tort" 220 per year,8 and "negligence" 400 per year.9)

What we do not see is any of the paraphernalia of "unjust enrichment" theory as expounded by its academic supporters. The phrase "unjust enrichment" is used almost entirely unadorned, as if no further explanation were required. Some judges have, indeed, declared openly that it is simply a matter of labels, and plaintiffs must bring themselves within some "recognised head" of restitution, meaning that they must justify their claim in the same way as if "unjust enrichment" had never been heard of; indeed, Lord Goff himself is often cited to that effect.'0 For many judges, then, references to "unjust enrichment" are simply a neat label for traditional remedies, but with no implication for the content of those remedies. "Unjust enrichment" no more refers to a particular theory of liability than "debt" does.

When we look for the elements of "unjust enrichment" theory, we see that the judges barely refer to them. We look in vain for references to "non-money benefits",1 or "symmetry",'2 or "separation of factors",'3 or "subjective valuation".'4 Single instances of the use of some

5 Much of the following paragraphs is based on material turned up by LEXIS searches for. UNJUST! W/10 ENRICH!, on the entire database of English cases. Other, more specific searches are indicated where relevant.

6 The.precise figures for the last 10 years are: 1985, 12; 1986, 6; 1987, 5; 1988, 9; 1989, 13; 1990, 8; 1991, 21; 1992, 17; 1993, 15; 1994, 17.

7 CONTRACT! AND DATE> 1989 AND DATE< 1995 returns 6,289 cases. 8 TORT! AND DATE> 1989 AND DATE< 1995 returns 1,132 cases. 9 NEGLIGEN! AND DATE> 1989 AND DATE< 1995 returns 2,077 cases. RESTITUT! AND

DATE> 1989 AND DATE< 1995 returns 203 cases, that is about 40 per year. Obviously these are very crude indices, particularly as all of these words might be used in a wide variety of contexts.

0 E.g. Westdeutsche Landesbank Girozentrale v. Islington LBC [1994] 4 All E.R. 890, 912j. What Lord Goff actually said was that "The recovery of money in restitution is not, as a general rule, a matter of discretion for the court. A claim to recover money at common law is made as a matter of right; and even though the underlying principle of recovery is the principle of unjust enrichment, nevertheless, where recovery is denied, it is denied on the basis of legal principle": Lipkin Gorman v. Karpnale [1991] 2 A.C. 548, 578de. Having identified the relevant principle, Lord Goff is of course by no means averse to developing the case law in accordance with it: see ibid., 580ch.

" NON-MONEY W/10 BENEFIT!: no relevant cases. 12 SYMMETRY: no relevant cases. 13 SEPARAT! W/5 FACTOR! AND (ENRICH! OR RESTITUT!): no relevant cases. 14 SUBJECTIV! W/10 (ENRICH! OR DEVALU! OR VALU!): no relevant cases, except Ashman

(following note).

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concepts may be found: there is a throw-away reference to "subjective devaluation" in Ministry of Defence v. Ashman;'5 there were references to "incontrovertible benefit" in BP v. Hunt'6 and The Manila,7 though in both cases the judge seemed to share the academic perplexity over how to use the notion.'8 In Marston Construction v. Kigass'9 Judge Bowsher Q.C. stuck his toe in the waters of "free acceptance", but rapidly withdrew it when counsel effectively abandoned that part of her argument.20 If "unjust enrichment" theory becomes a notable part of the common law, then future legal historians will see its first stirrings here-but in itself this is nothing much.

It is therefore a little early to say simply that the judiciary has "accepted" the theory of unjust enrichment; and the judicial tendency to avoid complex conceptions where the case can be resolved by simpler ones seems sufficient to steer the judiciary away from the theory in the future. "Unjust enrichment" can happily remain a mere label, with no effect on substance; or if the concept is in fact put to work, it may not be in ways the theorists would like. The route the judiciary will take in the future is necessarily unclear; but that they have not yet taken the theorists' path is clear enough. It is clear both from the judgments themselves, and from the critical comments of the theorists on those judgments.

(1) Language. "Unjust enrichment" theorists do not wish simply to introduce a new terminology, but also to disparage the old terminology of "implied contracts"; and so they criticise judges who use both as backsliders.2' Yet judges continue to use both, sorrmtimes even in the same sentence.22 Indeed, one of the more innovative judges (writing extra-judicially) recently concluded a fresh piece of theorising with this declaration: "A unified and comprehensive restitutionary remedy is capable of being developed by recourse to traditional equitable principles and terminology, as the present article demonstrates. For those who prefer, however, the arguments canvassed here can readily be translated into the currently more fashionable restitutionary language of unjust enrichment", adding in a footnote, "[t]hough

'5 (1993) 66 P. & C.R. 195, 201-202. 16 BP Exploration Co (Libya) v. Hunt (No.2) [1979] I W.L.R. 783, 805 DE 7 Procter & Gamble Philippine Manufacturing Corp. v. Peter Cremer GmbH, The Manila [1988] 3

All E.R. 843, 855-856. 18 INCONTROVERTIBL! W/10 ENRICH! and OBJECTIV! W/10 ENRICH! turn up no other

relevant cases. '9 (1989) 15 Construction L.R. 116. FREE! W/10 ACCEPT! AND RESTITUT! returns no other

relevant cases. 20 Ibid., 127-129. His brief comments on the scope of "unjust enrichment" were regarded as

"surprising" by Rattee J. in Regalian Properties p.l.c. v. London Dockland Development Corp. [1995] 1 All E.R. 1005, 1021-2, who went on to distinguish them.

21 E.g. Birks, Introduction, p.7.

22 E.g., "The action is one for money had and received and is based on unjust enrichment": Hone v. Canadian Imperial Bank of Commerce (unreported, 9 November 1989).

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582 The Cambridge Law Journal [1995]

whether that does anything to clarify the law is debatable".23 If that is

not a rejection of the theorists' view, it is certainly quite close to one.

(2) Use of academic writings. It is welcome that judges have felt

free to rely on academic writings, and the leading theorists can derive

some satisfaction in this regard.24 But they will look in vain for any references to, let alone endorsement of, the central concepts of "unjust enrichment" theory. This is not a topic on which they have been found

to be useful. This is of course not an unusual fate for English academic

writings, which only rarely seem to find favour with judges interested

in the same issues.

(3) Not referring to "unjust enrichment" theory. Academic criticism

of the judges' failure to use "unjust enrichment" concepts is pro- nounced and sustained, whether the charge is that the judges have

"not made it clear" how the theorists' analysis applies,25 or that they are describing non-restitutionary claims as restitutionary,26 or that

they rely on matters that are not recognised "unjust" factors,27 or that

their rulings show a "lack of technical craftsmanship"28 and sorely need "some rigorous scientific analysis".29 None of these is a sin except to one already committed to an "unjust enrichment" analysis at a high level of generality; indeed, some of them are barely comprehensible to

non-theorists, let alone recognisable as faults to be avoided. And

Millett L.J.'s recent deprecation of theories that are too subtle to apply in practice,30 and his assertion of the limited assistance that arguments over classification are to judges,31 cannot be much of an encouragement to the theorists.

The rare cases that turn directly on classification are not encourag-

ing either. In Friends* Provident Life Office v. Hillier Parker May and

Rowden32 the Court of Appeal held that restitution of money is

"damages" under the Civil Liability (Contribution) Act 1978; in

Barclays Bank p.l.c. v. Glasgow City Council, Hirst J. was prepared to

23 P. Millett, "Tracing the Proceeds of Fraud" (1991) 107 L.Q.R. 71, 85. Note that while in a sense "unjust enrichment" theorists too want a "unified and comprehensive" approach, they wish to unify and to comprehend a much wider range of cases, without so much in common with one another.

24 BURROWS AND (REST1TUT! OR UNJUST!) returns 4 relevant cases; a search for BIRKS returns 11 relevant cases. A search for Goff and Jones would be likely to produce more; the less theoretical the approach, the more popular with the judges. 25 Burrows, Restitution, p. 280.

26 Burrows, Restitution, p. 38. 27 Burrows, Restitution, p. 351. 28 P. Birks, "Property in the Profits of Wrongdoing" (1994) 24 University of Western Australia Law

Review 8, 12. 29 Loc. cit., p. 16. 30 P. Millett, "Bribes and Secret Commissions" [1993] Restitution Law Review 7, 15-16. Millett L.J.

was criticising the views expressed in R. Goode, "Property and Unjust Enrichment", in A. Burrows (ed.), Essays on the Law of Restitution (Oxford 1991), p. 215, which in all but a few details adopts the same analysis as Birks: see ibid. p. 221 n. 19.

31 Loc. cit., p. 18. 32 The Times, 15 April 1995.



"Unjust Enrichment"

find that a restitutionary action was an action neither "relating to a contract" nor "relating to tort, delict or quasi-delict" within the Civil Jurisdiction and Judgments Act 1982,33 but the Court of Appeal, saying that the matter was "far from clear", decided to refer it to the European Court of Justice instead.34 Plainly we are rather a long way from full recognition of restitution as an area entirely distinct from tort or contract; although arguably the problem here is not so much with judicial failure to recognise "unjust enrichment" as with Parliamentary failure to do so.

When we turn to the two leading cases, the same equivocal approach to "unjust enrichment" appears.

In Woolwich Equitable Building Society v. Inland Revenue Commis- sioners35 the plaintiffs paid over some £57m to the Revenue under statutory regulations, but then claimed that these regulations were ultra vires. They succeeded in having the regulations quashed, whereupon the Revenue repaid the money. The plaintiffs sought interest from the date of their own payment, thus raising the question whether they could have sued for the full amount, or whether the Revenue were making an ex gratia payment.

The judgment of the House of Lords in Woolwich's favour, and their assertion of the principle of unjust enrichment as they did so, are highly significant; and I have no quarrel with the result of the case. Yet it also shows the distinctly limited acceptance of the principle that the courts now offer, and the obstacles in the way of a fuller acceptance. The Lords' refusal to apply a theoretical "unjust enrichment" analysis is clear enough, as the theorists note: "If the law of restitution is not to descend into 'well-meaning sloppiness of thought', the unjust factor must be identified with greater precision";36 and it was considered that Lord Goff's attempt at theory was "unhelpful", "circular" and "begs the question".37 The theorists who insist on the significance of the case, as representing the coming-of-age of the theory, find themselves greatly at odds with the judges who decided it.

As for what the case tells us about future development, serious weaknesses in the "unjust enrichment" theory emerge. It is essentially a regime of private law rights. Applying these rights to the (public law) facts of Woolwich, the theory came close enough to confuse, but not close enough to apply: the case was almost-but-not-quite one of "mistake", and almost-but-not-quite one of "compulsion". The theorists have sought to include this class of public law case in their

33 [1993] Q.B. 429.

3 [1994] Q.B. 404. The European Court has now declined to rule on the point, saying that it is for national courts: Kleinwort Benson v. City of Glasgow DC, The Times, 17 April 1995.

3 [1993] A.C. 70.

36 E. McKendrick, "Restitution of Unlawfully Demanded Tax" [1993] L.M.C.L.Q. 88, 99. 37 Burrows, Restitution, p. 351.

C.L.J. 583




theory by tacking on "unconstitutional conduct" by the defendant as an additional "unjust factor", but as McKendrick concedes, in the current state of administrative law this raises more questions than it answers.38 We see restitution lawyers carving out their separate sphere using a view of the legal system that can only be described as antique: the Diceyan view, that we can and should judge the State by the same general rules as bind everyone else, finds few defenders today.39

In Lipkin Gorman v. Karpnale,40 which concerned the recovery of stolen money from the gaming club in which the thief had staked and lost it, we again see a result pleasing to the "unjust enrichment" theorists, justified by express reference to "unjust enrichment"-but again demonstrating no very obvious commitment to the theory. Lord Templeman's opinion relies heavily on "unjust enrichment", but that does not stop him using the old terminology of "money had and received"4' and "quasi-contract"42 as well; and at one point (to the theorists' consternation) he seems to adopt a proprietary theory of liability, of the type urged by Stoljar.43 Not content with Lord Templeman's ruling that the plaintiffs could have the money simply because it was theirs, the theorists reproach him with failing to identify any relevant "unjust" factor;44 in this respect his opinion apparently "exhibits . . . confusion",45 and overall there was a "disappointing" skewing of the argument as a result of counsel's concessions, and a "worrying" failure to set out the "unjust" factor, which may result in the case being "misunderstood as a property claim".46 Yet again, the theorists' contention that the judges have misunderstood the theory neglects the possibility that the judges have simply chosen not to apply it.

The main point in the case was the recognition of the defence of "change of position"; and as this aspect of the opinions does indeed

38 E. McKendrick, "Restitution of Unlawfully Demanded Tax" [1993] L.M.C.L.Q. 88, 96-97. 39 See J. Beatson, "Restitution of Taxes, Levies and other Imposts: Defining the Extent of the

Woolwich Principle" (1993) 109 L.Q.R. 401. 40 [1991] 2 A.C. 548. 41 Ibid., at 560a; so, for that matter, does Lord Goff, at 572f. 42 Ibid., at 566g. 43 Criticised by P. Birks, "The English Recognition of Unjust Enrichment" [1991] L.M.C.L.Q. 473,

482-483. 4 P. Birks, "The English Recognition of Unjust Enrichment" [1991] L.M.C.L.Q. 473, 475.

45 Burrows, Restitution, p. 141. 46 E. McKendrick, "Restitution, Misdirected Funds and Change of Position" (1992) 55 M.L.R. 377,

380-381. I have doubts over the merits of the claim, though they are not directly relevant to my thesis here. Why was the plaintiff firm's own negligence irrelevant? And why does a simple plea of "illegality" defeat the club's bonafide purchaser defence, given the 50-year-long tendency to treat executed illegal contracts as perfectly valid, at least in their proprietary consequences? Nothing was proved by way of knowledge against the club, despite strenuous efforts at first instance. ". . . [Olne must not let one's mind be prejudiced by the gambling context that there is behind the solicitors' claim against the club. The latter was licensed under the relevant statutes and its gambling activities were entirely lawful": Lipkin Gorman v. Karpnale [1989] 1 W.L.R. 1340, per May L.J. at 1350D.

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represent a judicial innovation based on "unjust enrichment" theory, it calls for comment. What needs particular comment is the great uncertainty it has introduced. It is manifest that it has not made the law more certain, but rather the reverse; at the moment, the doctrine is all questions and no answers. Attempts to expound it quickly degenerate into lists of points to which the writer would like answers47: How does one recognise a "change of position", or assess its extent? To what types of liability does it provide a defence? What is its relation to other defences? This uncertainty is all very different from what the

"unjust enrichment" theories promised, and stands as a warning to a future House of Lords, tempted to agree to yet further extensions of the law.

WHETHER WE USE "UNJUST ENRICHMENT" THEORY IS A CHOICE

Turning now to academic writings, the starting-point about "unjust enrichment" theory is that whether we use it is a choice, and that choice needs to be made on defensible grounds. At one extreme, the

very concept could be eschewed: we could (as lawyers once did) describe restitutionary liabilities without mentioning it, and rigorously avoid the words "unjust" and "enrichment". But no living writer defends this position. At the other extreme, we could refer everything to it : we could maintain that all restitutionary liabilities must be justified by some conception of "unjust enrichment" and that any case which does not fit is either wrong, or part of some other branch of the law. The question is where between the extremes to position ourselves. How much should we use concepts derived from "unjust enrichment" in defining restitutionary liabilities? Does spelling them out help, or does it hinder? Should we refine them further? Should we discard them? It is on this issue that I am against "unjust enrichment" theory. In a sentence, my argument is that the subject is currently over- theorised. At one time-say a decade ago-it was not unreasonable to argue for increased attention to theory. But this has turned out to be a dead end. Further refinement of "unjust enrichment" concepts has not clarified the law; and by assuming that there is an overall theory into which the major instances of liability will fit, we have loaded

47 E.g. Burrows, Restitution, pp. 424-431. Burrows concentrates on private law issues; the case law has so far not only failed to resolve these issues, but has added some public law issues for good measure: see South Tyneside M.B.C. v. Svenska Internationalp.l.c. [1995] 1 All E.R. 545; Kleinwort Benson Ltd v. South Tyneside Metropolitan Borough Council (unreported, 12 March 1993); R v. Secretary of State for the Environment, ex parte London Borough of Camden (unreported,

.17 February 1995).

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ourselves with the unnecessary difficulty of saying what it is. As a vague phrase, "unjust enrichment" is tolerably clear; let it be so used.

One might expect acknowledgement of choice to be very much to the surface in Birks' Introduction, because it is so openly concerned with urging a change of direction, substituting rather precise notions of "unjust enrichment" for older ideas. Equally, one might expect choice to receive less emphasis in textbooks such as Burrows' Restitu- tion. Every textbook must necessarily take a point of view; expositors must take what they believe to be the best organising concepts on offer. It would therefore have been entirely understandable if Birks argued that reason should guide us as to the theory, but that the theory picked out as the best should be expounded dogmatically by the textbook writers who followed.

What we see in fact is not quite like that. There is of course diversity: Tettenborn's Law of Restitution48 pays much less attention to theory than does Goff and Jones' Law of Restitution49 or Burrows' Restitution. The interesting thing is that the theory in each of these books, in most cases largely deriving from Birks' dogmatic Introduction to Restitution, agglomerates in the front of each book, while making little appearance in the main bulk of it. The theory is dogmatically stated in the first instance, yet largely ignored from then on. The actual exposition of the law proceeds without very much reference to the theory which dominates the early pages. So Tettenborn gets on with the business of expounding the law of restitution while virtually ignoring the concept of "unjust enrichment".50 To a very great extent, so do Goff and Jones: one may go for many dozens of pages without a reference to "unjust enrichment" or any of the theories derived from it.51 And even Burrows, the most theory-oriented of the textbook writers, prefers to talk of the nitty-gritty of the cases, only occasionally breaking off to ask how all of this may be reconciled with theory.52 It is quite unnecessary for me to argue that the law of restitution might in principle be expounded without reference to an elaborate "unjust enrichment" theory. By and large, it already is, even by those most forthright in promoting the theory. Yet some of those same expositors still teach "unjust enrichment" theory, and maintain that it is essential to an understanding of the subject. What are we to make of the theory?

4 London 1993. 49 4th ed., by Gareth Jones (London 1993) (hereafter Goff and Jones). 50 A. Tettenborn, Law of Restitution (London 1993); only chapter 1 can be said to involve itself in

theory to any significant extent. 51 The theory here is almost entirely in chapters I and 2, being little in evidence in the remaining 41

chapters. 52 For example at p. 242. The earlier parts of that chapter avoid the matter. See further at note 59

below.

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THE THEORISTS' CONCEPTION OF "RESTITUTION"

The different theorists each have subtly different views. Nonetheless, a conception of the subject which seems to unite them goes something like this. In earlier years-say, before the first edition of Goff and Jones in 1966-restitution was unjustifiably ignored by courts and academics alike. But now we have outgrown all of that. Having disposed of the claims of rival theories, restitution is now a subject in its own right, like contract or tort; like them, the intuitive moral appeal of the subject holds it together, and provides a solid foundation for a more theoretical approach.

If this conception were true to the facts, the need for a solid underlying theory would be powerful indeed. Let us take the individual claims one at a time.

A. Unjustified Neglect of Restitution in Earlier Years

This should not be a problematical claim. What is meant by it is that judges of earlier generations did not think of restitution as a single unit, let alone as a single unit united by common principles. This is perfectly true. What would not be true, and would indeed be an entirely different claim, is that earlier generations of judges had no time for restitutionary issues, or that earlier generations of academics neglected restitutionary problems. Restitutionary issues were com- monly debated, and will be found all over the contract, equity and property books. What was missing was a treatment of all of these problems in one book, and the elaboration of a theory to link them all together. The self-image of "unjust enrichment" theorists as "frontiersmen"53 conceals, as so often in the past, a certain disregard for the original inhabitants.

All this is, I imagine, clear enough. The charge of "neglect" of restitution is not really a charge of laziness at all, but simply a roundabout way of saying that our predecessors were making a theoretical mistake, by seeing chaos and disorder where there was in fact order. The real charge against earlier writers is not neglect but balkanisation; and this conclusion allows the theorists to slide quickly over the substantive question, which is whether restitutionary materials belong together.

B. Rival Theories

One argument that is widely used in support of "unjust enrichment" theory is its supposed ability to explain the imposition of liability over

53 M. Garner, "The Role of Subjective Benefit in the Law of Unjust Enrichment" (1990) 10 O.J.L.S. 42.

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a wide range of cases. For many of those cases, taken alone, other explanations are plausible: property, tort, contract, various

miscellaneous equitable doctrines, or notions of "unjust sacrifice"

could each be invoked in some cases. But only the theory of "unjust enrichment" covers all cases, and it is this consistent application that

demonstrates that it is the true explanation of these cases.54

Yet there is no one determinate list of doctrines that call for

explanation. To say that Stoljar's theories of "property" and "unjust sacrifice" must be fallacious because they cannot explain all cases of

"unjust enrichment"55 begs the question, the question whether there is

a body of restitutionary claims in need of explanation. I will come on

to the weaknesses of the "unjust enrichment" theory itself. My point here is that to criticise other theories for only explaining part of

restitution is to assume the very point in issue, namely whether there

is a determinate "restitution" in need of explanation. The search for a

unified explanation may be a pseudo-problem.56 In fact, the range of doctrines that "unjust enrichment" has been

thought to explain has varied considerably across the years; and the

rise of precise theory has resulted in a narrowing of the subject.

Unsurprisingly, we see that the more precise the theory, the fewer the

instances of liability it can be used to explain.57 And so we see the emerging split in text-book treatments: the initial theoretical

controversies over the meaning of "benefit", and the subsequent

exposition of the law without reference to it: the gap between them

growing with every new edition. For example, Burrows still declares

that a law of restitution without a single theory behind it is hard to

understand and threatens to make the entire subject pointless,58 yet then expounds much of the law without reference to any theory,

pausing only occasionally to ask how the law and theory may be

reconciled;59 or he may start a chapter with a bold declaration that theoretical symmetry "demands" a certain type of liability,60 and only later in the chapter admit that "in practice" it is not to be found in the cases.61 And the temperature of the debate seems to be cooling: for

54 For example Burrows, Restitution, pp. 1-6 55 Burrows, Restitution, p. 4. 56 In Birks' terminology, my claim is that if restitution is rightly to be regarded as a category at all,

it is a contextual category: see Birks, Introduction, pp. 73-74. 57 So Goff and Jones now contains much material that "unjust enrichment" theorists would not

regard as part of their subject: ch. 27, 29, 30, 34 and 37. 58 Burrows, Restitution, p. 6. 59 See for example Burrows, Restitution, ch. 5,9 and 10: it is hard to find anything in these chapters

that even the most passionate opponent of "unjust enrichment" could object to, except of course for the jargon of the theory, which adds little and could be edited out without changing the substance. In ch. 6 and 11, we see short theoretical introductions, and then the body of the text follows the same pattern. 60 Burrows, Restitution, p. 250 (restitution for benefits in kind conferred by a contract-breaker on the other party). The "symmetry" is with the equivalent case where the benefit is money. 61 Burrows, Restitution, p. 276.



"Unjust Enrichment"

example, initial attempts to claim the remedy of rescission of contracts for restitution alone have quietly been turned into the lesser claim that it is really part of contract but also part of restitution.62

Special mention must be made of the "central area"63 of restitution: claims for money paid by the plaintiff to the defendant as a result of mistake or pressure, or on a consideration which fails (in traditional terminology, claims for "money had and received"; in "unjust enrichment" terminology, "money claims for unjust enrichment by subtrac- tion"). Explanations for the recovery in these cases abound: we can say that the plaintiff recovers because the defendant is unjustly enriched at her expense, or that the plaintiff is recouping a loss suffered, or that the remedy is part of the protection the law affords the plaintiff in respect of her property. There is very little to choose between these explanations, any of which would be quite good enough as a thumb-nail sketch of the law; what is lacking is any reason for thinking it matters which one we choose. The argument only arises because the theorists treat these cases as mere examples of "unjust enrichment", seeking then to expand the category in two ways: firstly to cover other types of benefits besides money, and secondly to describe quite different heads of liability. They take the "central area" as the core example of restitution for unjust enrichment, and then seek to expand the core to other cases that "logically" should be no different.

Yet (as I will show in detail below) this attempt has largely failed. Having brought money cases within their theory by saying that the money is a benefit unjustly gained, "unjust enrichment" theorists thus create a problem for themselves, namely that of what "benefit" means in relation to other forms of value, and what the law on the recovery of those benefits looks like. This problem they have failed to solve. The main thing "unjust enrichment" theory seems to promise, namely consistent application of a small set of key principles over many situations, is illusory. The charge of vagueness64 and of over-stretching of concepts65 they make against other theories can be thrown straight back. No one theory explains every important feature of these cases; a number of theories give a rough picture of it; the superiority of any one theory is not evident.

The oddity of all this needs some emphasis. What other legal discipline, whether emerging or well established, goes through this kind of rhetorical exercise? Of what use is this rigid theorising and

62 Burrows, Restitution, p. 34. 63 Burrows, Restitution, p. 95. 6 P. Birks, "Civil Wrongs: A New World", Butterworth Lectures 1990-91 (London 1992), pp. 74-

77, criticising Stoljar's "unjust sacrifice" theory. 65 Burrows, Restitution, pp. 393ff, criticising Sharpe and Waddams' "compensation" theory (see

R.J. Sharpe and S.M. Waddams, "Damages for Lost Opportunity to Bargain" (1982) 2 O.J.L.S. 290).

C.L.J. 589




drawing of boundaries-boundaries aimed not so much at expounding the law as at staking an academic claim to a particular set of cases? Contract and tort scholarship has recently progressed very happily without asking whether they are distinct from restitution; only restitution theorists have regarded the matter as crucial. The precise line between contract and tort is much disputed, but it has not been suggested that the identity, still less the existence, of either turns on how this point is resolved. Elsewhere, it is taken for granted that the boundaries between legal doctrines are only rarely important. And all other areas can justify their existence without demanding adherence to a theoretical dogma: the reasons why administrative law, planning law and tort are important have nothing to do with any particular theory of liability. Only in restitution are we told that the subject is important because underlying it there is an important theory of liability.

C. A Subject like Contract or Tort It is astonishing how often restitution theorists compare their subject to contract and tort.6 And Birks at least is quite explicit that most legal subjects are not like contract and tort; rather, they are "contextual"67 subjects which "have no unity of concept and event"68 Labour law, for example, is "contextual", because its textbooks gather together all the law that is relevant to labour cases, whatever category a stricter theorist might place it in. Birks is not making the (very plausible) argument that labour law is a controversial area, bearing the imprint of many incompatible approaches over the years, and is therefore somewhat incoherent. He is arguing that labour law is by definition incoherent, as is any subject not grounded in a coherent, rigorous and purely legal theory of the type he favours. By collecting "all the law there is about the particular aspect of life which interests you", their theoretical purity is necessarily compromised.69

What areas, other than restitution as the theorists imagine it, satisfy this criterion ? It is hard to see how any area concerned largely with statute law can possibly do so. Strict English attitudes to statutory interpretation effectively forbid interpretation by reference to a framework of theory not expressly spelled out in the statute itself-which seems to be why Birks fears that statutory development of restitution will be at the expense of the theoretical purity he seeks.70 Yet once we have abandoned statute law we have abandoned most of the modern

E.g. Burrows, Restitution, p. vii. 67 Birks, Introduction, p. 74. 68 Birks, Introduction, p. 73. 69 Birks, Introduction, p. 74. 70 Birks, Introduction, pp. 261-264.

[1995] 590



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legal system. And the remaining case law areas do not, by and large, demonstrate much by way of theoretical coherence. Property law, whether real or personal, certainly does not, displaying the eclecticism that the restitution theorists shun. Tort is little more than a jumble; overall coherence can certainly be given by viewing the various torts as protecting the various "interests" a plaintiff might have,7' but no- one argues that this sort of analysis is of much use in understanding the detail of doctrine; and Burrows' reference to "the mire into which the English tort of negligence has recently sunk"72 hardly suggests that he wants to take that as a model. Equity's coherence, if such it is, is only comprehensible as a matter of history; and "unjust enrichment" theorists are not anxious to emphasise the claims of equity, as it is a rival category-the possessor of large tracts of territory that restitution theorists claim as their own.73

When we look for a model on which "unjust enrichment" theorists would be happy to base themselves, there really is only one, namely the general law of contract. The prestige of this century-old academic creation is quite openly coveted by restitutionary theorists. Moreover, they have a very particular view of the law of contract, in several ways more akin to the view generally held 50 years ago. What modern contract theorist believes that the subject can be summed up by references to "the will of the parties"? This is not the place to assess the role of these ideas in the modern law, and it is no part of my case here that they have no place. Yet the conception of contract assumed by the restitution theorists is not considered satisfactory by any significant number of contract scholars.74 Even Fried, who amongst contemporary contract theorists is the most insistent on the role of the parties' will, maintains that it is an error to refer all contractual issues to it, "as if relief had to be either based on a promise or denied altogether".75 It would be unfair to describe the "unjust enrichment" theorists' view of contract as "conservative"-unfair, that is, to the real conservatives, who believe nothing so simple.76

71 E.g. P. Cane, Tort Law and Economic Interests (Oxford 1991); S. Hedley, "Contract, Tort and Restitution: or, On Cutting the Legal System Down to Size" (1988) 8 L.S. 137.

72 Burrows, Restitution, p. 361. 73 See e.g. Birks, Introduction, p. 39; P. Birks, "Civil Wrongs: A New World", Butterworth Lectures

1990-91 (London 1992), p. 55. 74 For fuller treatment of this point see J. Beatson, "Benefit, Reliance, and the Structure of Unjust

Enrichment" [1987] C.L.P. 71. It is not entirely clear whether Burrows goes as far as Birks on this issue, though his insistence that there is a difference between contract, on the one hand, and unjust enrichment based on a "bargained-for enrichment", on the other (Restitution, p. 15), certainly suggests that he takes a rather rigid view of contract.

75 C. Fried, Contract as Promise, Harvard 1981, p. 6. 76 For a review of competing theories generally see B. Coote, "The Essence of Contract" (1988) 1

J.C.L. 91.

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D. The Intuitive Moral Appeal of Unjust Enrichment

It is of course hard to deny the moral appeal ofa principle of removing benefits unjustly acquired. It is the attempts to pin it down that fail.

The word "unjust" should not be lightly invoked. In most areas, as a

tool in legal argument the principle is vacuous: when the true argument is over what justice demands, merely to repeat that we will reverse

unjust enrichments if we find them advances the argument not one

inch. This sort of morality has no back-bone. In the areas where an

appeal to justice has some bite, moreover, we see "unjust enrichment"

slipping from the theorists' grasp: the demands of morality seem not

to fit into their rigid theoretical scheme.

In the central area, it seems tolerably clear that the moral principle does not help very much. Burrows lists eleven principal "autonomous

unjust factors", failing into no particular pattern; he admits that they

operate only at "a general guiding level", and that the list "does not

itself specifically answer what the law regards as unjust enrichment".77

He concedes that to elaborate on the matter further would be likely to

reduce clarity rather than increase it.78 Indeed, the reference to injustice seems to hinder more than it helps. As Scott points out, it is analytically rather dubious to assert that restitutionary claims are designed to

avoid injustice, as this suggests that other legal claims have a different, and less important, objective.79

Moreover, given the theorists' conceptualisation of contract as

exclusively based on the will or intention of the parties, the area has

become a magnet for those of an individualistic bent, who would

prefer most civil liability to be so based, and are suspicious of liabilities

that the parties have not imposed on themselves. Such writers are of

course unlikely to find the modern law of contract or tort very

congenial, and quite a few have migrated to restitution, where they find the individualist's last redoubt. So when Birks innocently remarked

that householders are bound to pay those who have cleaned their

windows, at least if they deliberately hide themselves in the knowledge that the cleaner is likely to clean first and ask questions later, he found

himself set upon by other theorists whose sensibilities were outraged

by this view of the law. The householder may be acting in a "shabby"

way, says Burrows, but is nonetheless acting lawfully.80 And Mead

opposes any relaxation of the strict contractual approach: contract

77 Burrows, Restitution, pp. 21-22. 78 Burrows, Restitution, p. 77 (discussing subrogation). 79 S.R. Scott, "The Remedial Constructive Trust in Commercial Transactions" [1993] L.M.C.L.Q.

330, 353. 80 A. Burrows, "Free Acceptance and the Law of Restitution" (1988) 104 L.Q.R. 576; Burrows,

Restitution, pp. 12-15, 315ff.



C.L.J. "Unjust Enrichment" 593

law, he says, is right to insist on a distinct promise.81 Plainly, this

approach undermines restitutionary liability considerably. If liability to pay for commercial services must be based on contractual principles, and contract is entirely distinct from restitution, then by definition restitution has no role to play. Leaving restitution in the care of

avowed individualists is like leaving a starving rabbit to guard an

especially succulent lettuce.

The same dilemma dogs the discussion of restitutionary remedies

for breach of contract. Either the remedy the plaintiff seeks can

be accommodated within contractual notions, in which case it is

presumably not restitutionary, or it cannot, in which case individualists

will oppose it as subverting the parties' bargain. With slightly more

awareness of contract law, this would all clearly be revealed as a non-

problem. Very little ofthe range of contractual remedies can really be

said to have been the product of the parties' joint will. Yet attempts to point out that the legal consequences of contracts are necessarily

provided by the law, not by the parties, are dismissed by the theorists

as the fallacy ofthe "implied contract" in new guise.82 So as used by the "unjust enrichment" theorists, the moral principle

of unjust enrichment is vacuous: the theorists are too wary of

statements as to the injustice or otherwise of particular remedies for

the concept to do any useful work. An account of what "unjust" might mean can be provided simply by a description of what the law is.

Indeed, Birks deprecates further elaboration of "unjust", on the

ground that it would involve judges in political issues.83 The reference

to injustice therefore seems to add nothing, except the trite observation

that whereas before Goff and Jones all we knew was that the law gives a remedy in these cases, nowadays we know that it does so in order to

avoid injustice. This is not to decry the very fine work that restitution

theorists have done in defining the limits of recovery and debating its

reform. This is what they should be doing, and they do it well. What

they should not be doing is to try to fit everything into a theoretical

structure which does nothing to advance understanding, or to give the

impression\that there is a neat theoretical solution to be had. In the contexts where the appeal to injustice is not vacuous, it is

clear that the direction in which it takes the subject is by no means to

the "unjust enrichment" theorists' liking. For one thing, it is no part of the moral principle that restitution is distinct from other areas of

the law. It requires no deep insight into property law to see that it is

very largely concerned with which enrichments are just and which are

81 G. Mead, "Free Acceptance: Some Further Considerations" (1989) 105 L.Q.R. 460. 82 E.g. Burrows, Restitution, p. 274, criticising Dies v. British and International Mining and Finance

Corporation [1939] 1 K.B. 724. 83 Birks, Introduction, pp. 19, 178.




not. And the reasons why we enforce promises are not unrelated to

the unjust enrichments that would accrue if we did not.84 Many of the

cases where morality cries out for the removal of an enrichment turn

out to have nothing to do with "unjust enrichment" as defined by the

theorists. So, for example, while it is obviously just that murderers

should not be allowed to benefit under their victims' wills,85 the claim

that this has anything to do with restitution has been quietly dropped as "unjust enrichment" theory grows more precise: it is simply not

part of, or analogous to, any of the claims that "unjust enrichment"

theorists are concerned with.86 The claims of morality are something of an embarrassment in that regard.

As more and more precise theory heightens awareness of just how

different the various areas of restitution are from one another, it is

becoming clear that the recovery of benefits gained by unlawful means

cannot be fitted into the same framework as the central area. These

cases can only be fitted into the framework of "unjust enrichment at

the plaintiffs expense" if we give "unjust" and "expense" quite different meanings from those given elsewhere; there are also the

perennial problems involved in defining non-monetary benefits.87

Whether removing the gain flowing from a wrong is defensible needs

consideration in the context of other remedies for that wrong, not

abstraction into a "restitutionary" issue; and if the aim of the removal

ofthe gain is to punish, then a measure of judicial discretion is needed

to determine the justice ofthe punishment.88 Moreover, to say that the

law recognises an enrichment as unjust is only the start of the enquiry as to the appropriate remedy, and a theory that proposes simply the

identification and removal of the benefit is too rigid for the task at

hand.89 So the chasm between the central areas and the rest of the

subject broadens yet more; and the leading theorists back away from

innovation, saying that they do not want the courts to be able to

identify and remedy any instances of unjust enrichment not already covered by a remedy.90

P.S. Atiyah, Promises Morals and Law (Oxford 1981). E.g. In re Sigsworth [1935] Ch. 89. So Burrows does not consider this to be part of restitution; Burrows, Restitution, p. 380. He gives two reasons: first, that the murderer is prevented from enriching himself, rather than having an unjust enrichment removed from him; and secondly, that the enrichment is not at the expense of anyone in particular. For debates here see for example J. Beatson, "The Nature of Waiver of Tort", in Use and Abuse of Unjust Enrichment (Oxford 1991), 206; R. O'Dair, "Remedies for Breach of Contract: A Wrong Turn" [1993] Restitution Law Review 31. Cf A. Freiberg, "Confiscating the Literary Proceeds of Crime" [1992] Crim. L. R. 96. See also P. Birks, "Civil Wrongs: A New World", Butterworth Lectures 1990-91 (London 1992) p. 80ff, opposing discretionary remedies in restitution. N.J-. McBride and P. McGrath, "The Nature of Restitution" (1995) 15 O.J.L.S. 33. 1 Burrows, Restitution, pp. 38, 54-56; Birks, Introduction, pp. 18-19, 22-25.



"Unjust Enrichment"

DOES THE THEORY CLARIFY THE LAW?

We could certainly get by without "unjust enrichment" theory; indeed, in many areas of restitution the law not only can be but is expounded entirely without its aid. Are we, on the whole, better off with theoretical attempts to define and expound key theoretical terms? I argue not. The theory has done little to clarify the law, and has simply added to the labour of those who study it, firstly by the insistence on a double set of terminology-for even if we accept that expressions such as "implied contract" and "money had and received" are outdated, it remains true that one cannot understand the cases without them-and secondly, by posing the problem of how the law may be reconciled with the theory. The assertion that restitution consists of the "recovery of benefits unjustly gained" leads on to the question of what these expressions mean; and after a decade of active debate, it is clear that nobody quite knows. I must repeat that I have no quarrel with the work of the leading theorists when they merely describe the law, or discuss possible reforms; very much the contrary. But the merits of these writings come when they ignore the theoretical framework, and simply describe the law without it. The theoretical framework, insofar as it has any effect at all, is unhelpful.

The theorisation of the subject is uneven. There has been no very concerted attempt to state "unjust" factors or defences in anything other than unstructured lists of "unjust factors".9' Other theoretical entities have made brief appearances. The theorists have toyed with notions of causation.92 And at a time when they still harboured a hope that "unjust" factors could be systematised, there was talk of a doctrine of the "separation of factors". What this meant was that if there were coherent definitions of both "injustice" and "enrichment" which did not lapse into tautology, presumably they would identify different features of the same case. One could not point to the same fact and say that it was both proof of injustice and proof of enrichment. However, Birks was soon driven to admit that this condition was not satisfied in "free acceptance" cases,93 and the idea has been quietly dropped since that time.9 The main part of the theoretical argument has been over the meaning of "benefit" or "enrichment" (the two terms are virtually synonymous).

91 For a rare attempt to introduce a little more theory here see Burrows, Restitution, 141. 92 E.g. Burrows, Restitution, pp. 23-27. 9 See Burrows, Restitution, pp. 12-13. 94 Burrows makes occasional reference to the concept: e.g. Restitution, pp. 13, 16.

C.L.J. 595




"Benefit"/"Enrichment"

This issue is central. If it is possible to give a clear meaning to the expression "benefit", such that the law clearly allows recovery of "benefits" in restitutionary cases (subject, no doubt, to various conditions), then clearly we have a phenomenon worthy of note, which notions of "unjust benefit" are likely to be helpful in describing. If however the law can only be explained by giving multiple meanings to "benefit", with no very obvious pattern to the various meanings and no very clear criterion of liability, then the utility of the theory is less obvious. After all, whenever a remedy ought in justice to be available, we can loosely describe a refusal to grant it as causing an "unjust enrichment", and granting it as the removal of the enrichment- whether the remedy is part of contract or restitution, tax law or criminal law. The inconclusive result of the theoretical debates over the meaning of "benefit" is therefore of immense importance; and the implicit promise of the early chapters of restitution textbooks, that the subject can be expounded on the basis of this notion, is broken.

It is no exaggeration to say that every contributor to the debate has had a different idea of how to answer this question. Yet the insistence on "symmetry"-that whatever can be said of money benefits must in principle be sayable about other benefits as well-has been none the less for that. Indeed, Birks has even asserted that "[n]o rational distinction" can be drawn between appropriating the value of land and appropriating the value of another's services95-a proposition which is bound to startle land lawyers and employment lawyers.

The symmetry is broken in practice, of course. There are many situations where money benefits are recoverable yet there is no sign that other benefits are recoverable, or indeed of how they would be valued for that purpose. The theorists' discussions of this state of affairs typically start with the bold assertion of "symmetry" and the irrationality of denying it, yet end with the admission that in this respect the common law may be irredeemably irrational.96

My point is not that it would be undesirable for the law to show "symmetry". My points are that it does not; that it has not yet been made clear how it could do so, as the differences between the types of benefit are implicit in the nature of the assets concerned, not mere accidentals that theory can strip away; that it is pointless to accuse the courts of irrationality when no alternative is on offer; and that the debate has not clarified the law in any significant respect.

It is easy to value money benefits. If I receive £500 which I would

95 Birks, Introduction, p. 324. 96 E.g. P. Birks, Restitution-The Future (Sydney 1992), ch. 4.

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not otherwise have received, then £500 is the measure of my enrichment. With other types of enrichment it is not so simple. I receive goods which cost £500 to purchase. How is this benefit to be valued? In some circumstances £500 will be the right figure. But I may deny that I have been saved £500 by this receipt, and insist that some other measure is

appropriate; or indeed I may deny that I have been enriched at all; or

you may argue that my actual gain is higher still. How are these pleas to be treated?

"Subjective devaluation". It is said that benefits may sometimes be "subjectively devalued": that is, the recipients may lawfully deny that benefit, on the ground that they do not themselves regard it as being of value. Yet no coherent account of when this applies is to be had.97 It is simply a catch-all for cases where no restitution is allowed.

"Objective benefit". This is the mirror-image of "subjective valuation": in certain circumstances, a plea of "subjective devaluation" will be defeated by the existence of a benefit established by objective criteria. If no reasonable person would deny that the defendant is benefited, then neither can the defendant. Again, the theory is useless because it is so unclear when it can be invoked. The only case where the argument clearly applies is where the benefit consists of money: the one case the theory clearly explains is the one where it is unnecessary! Other cases have been tentatively suggested: where the defendant has been saved an inevitable expense; or (controversially) where the defendant is in receipt of services.98 It is clear that there is no agreement on a definition, and that none of the theories proposed bears much resemblance to the actual law on the topic.

"Incontrovertible benefit". This is a similar idea. Yet on what grounds may a benefit be deemed "incontrovertible"? Again, tentative suggestions are thrown out-the saving of a necessary expense, or a benefit realisable in money9- but while a few isolated examples of this measure have been adduced, there are only hints of an overall description of when this measure might be available;10° and controversies remain.101 Meanwhile, there are hints of a more moralistic approach: it is argued that because we all ought to perform our legal duties, therefore a plaintiff who carries out a defendant's duty "incontrovertibly benefits" that defendant;102 or again, a defendant who obtains a benefit by reprehensible means may not be allowed to

97 E.g. Birks, Introduction, pp. 110- 114. 98 See review of theories in Burrows, Restitution, pp. 8-9. See also Mead's attempt to fuse objective

and subjective aspects of benefit into a single theory: "Restitution within Contract?" (1991) 11 L.S. 172, 187.

9 Goffand Jones, p. 23. 00 See for example Birks, Introduction, pp. 116-128. '01 See for example the criticisms of Burrows, Restitution, p. 10. 102 E.g. Burrows, Restitution, p. 232.

C.L.J. 597




dispute the court's assessment of its value.103 This is of course the same intellectual manoeuvre the theorists have long condemned in another context: just as the courts of old would not allow a defendant to deny an "implied contract" when it was unfair to do so, even though it might have been accurate, so now the "unjust enrichment" theorists deny that a "benefit" had been subjectively devalued by a morally unattractive defendant. Replacing "implied contract" with "benefit" does not avoid fictions, it simply changes their names.

"Free acceptance". The meaning of this is at least clear; yet (perhaps not entirely by coincidence) it is even more controversial amongst the theorists. Goff and Jones still support it;'0 Mead rejects it;'05 Burrows also rejects it, though he supports the somewhat similar notion of "bargained-for" enrichments;'06 and Birks has retreated somewhat from his earlier support for it, though he currently defends a narrower conception.07 The similarity with contractual liability is obvious; Birks and Burrows still insist, plausibly, that in some cases at least "free acceptance" falls outside a conventional understanding of contract;'08 they do not explain why they prefer to stretch "enrichment" notions, which do not fit at all, rather than contractual ones, which almost do.

Concepts of enrichment, then, are diverse, and attempts to pin them down simply emphasise the diversity. The theorists have not yet won the right to decry other approaches as "palm-tree justice",'09 for they have presented nothing better. No one theory of enrichment is shared even by two theorists; the prospects for obtaining the agreement of the entire legal community seem bleak indeed. And to invite the judges to accept the current theoretical approach is not to invite them from the realm of darkness to a realm of light, but simply to a new type of darkness.

THE FUTURE

In summary, then, we see in the cases great interest in restitutionary issues, and (on occasion) a willingness to make quite spectacular changes in the law when the judges' moral feelings are sufficiently outraged. "Unjust enrichment" theorists claim to support these devel-

103 E.g. Burrows, Restitution, pp. 164-165. 104 Goff and Jones, pp. 18-22. 105 G. Mead, "Free Acceptance: Some Further Considerations" (1989) 105 L.Q.R. 460. 106 Burrows, Restitution, pp. 11-15, 315-320. 107 See especially "In Defence of Free Acceptance" in A. Burrows (ed.), Essays in Restitution

(Oxford 1991), ch. 5; Restitution-The Future (Sydney 1992) pp. 56-60. p08 P. Birks, Restitution-The Future (Sydney 1992) pp. 53-54, and Introduction, pp. 270-271;

Burrows, Restitution, p. 15. '09 P. Birks, "The English Recognition of Unjust Enrichment" [1991] L.M.C.L.Q. 473, 475.

598 [1995]



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opments, but in fact only favour them when the judiciary accepts a narrow and precise theoretical conception of the subject; as a result, the theorists seem to spend much of their time correcting the classificatory "misunderstandings" of the judges."° Yet the judiciary seem to have no time for this; mere classification butters no parsnips.

What of the future? In a few decades, will the cry that "[t]he categories of unjust enrichment are not closed""' be a heresy, or a tradition of the common law? (A newly-minted tradition, to be sure- but then the better traditions often are of recent coinage.) There is no reason to expect that interest in "unjust enrichment" ideas will diminish. They are a convenient way of discussing minor injustices that can be corrected by small changes to legal rules. And their increasing use in statute law,"12 and the likely influx of European legal ideas,113 will give them further momentum. Yet the very different ways in which they are used in these different contexts will be another pressure for diversity. Having given the judiciary this shiny new toy to play with, the theorists are now realising that they are not in a position to control its use-and that the theorists' own ideas would prevent its use for the very projects the judges favour.

None of this will surprise those who have read Atiyah's The Rise and Fall of Freedom of Contract,"4 charting the century-long rise of values compatible with unjust enrichment, at the expense of more individualistic Victorian ideals. The "unjust enrichment" theorists have only absorbed half this message. They have appreciated that claims of "unjust enrichment" are coming into vogue; and this is perhaps why they feel free to describe those with ideas different from their own as "flat-earthers"."5 Those of us who oppose the rigid formalism of the theorists must concede the rise of "unjust enrichment", and go further: it is not confined to any one area of legal discourse; like sand on the beach, it gets everywhere; and this is precisely why it cannot be confined in any rigid theoretical schema. Whether these notions are a stepping stone to a fuller picture of the law, not needed by all but perhaps necessary for "Goff and Jones, Lord Denning, Professor Birks and other lesser mortals","6 remains to be seen. But viewed in the long term, their future looks grim.

"0 Theorists tend to discuss this issue under the rubric of the "generalised right to restitution", a bugbear to them : see for example Birks, Introduction, p. 27. Early editions of Goff and Jones supported a general right, but Jones now seems to require "scrupulous [conceptual] analysis" as well (Jones, "The Law of Restitution: the Past and Future", in Burrows (ed.), Essays on the Law of Restitution (Oxford 1991), p. 3)-a position not obviously different from Birks'.

" Per Sir Donald Nicholls V-C, CTN Cash & Carry v. Gallaher [1994] 4 All E.R. 714, 720d. 12 See Value Added Tax Act 1994, s. 80(3); Finance Act 1994, Sch. 7, para. 8(3); Finance Act 1989,

s. 29(3); Torts (Interference with Goods) Act 1977, s. 7(4). '3 See for example Cotter v. Minister of Social Welfare [1991] I.R.L.R. 380.

14 (Oxford 1979). The passage critical of "unjust enrichment" theory is at p. 768. 15 P. Birks, "The English Recognition of Unjust Enrichment" [1991] L.M.C.L.Q. 473. 16 W.R. Cornish, "'Colour of Office': Restitutionary Redress against Public Authority" (1987) 14

Journal of Malaysian and Comparative Law 41, 56.

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Unjust Enrichment