1 Burrows, A., “Quadrating Restitution and Unjust Enrichment: A Matter of Principle” [2000] R.L.R. 2; Goff, Lord and Jones, G.H., The Law of Restitution (6th edn., London 2002) 4Google Scholar.

2 M.P. McInnes, “Restitution, Unjust Enrichment and the Perfect Quadration Thesis” [1999] R.L.R. 118; Birks, P., “The Law of Restitution at the End of an Epoch” (1999) 28 West. Aust. L.R. 13Google Scholar; Virgo, G.J., The Principles of the Law of Restitution (Oxford 1999), 17Google Scholar.

3 Virgo, ibid. Grantham, R. and Rickett, C.E.F., Enrichment and Restitution in New Zealand (Oxford 2000)Google Scholar, chap. 3.

4 Birks, P., “Definition and Division: A Meditation on Institutes 3.13” in Birks (ed.), The Classification of Obligations (Oxford 1997)Google Scholar chap. 1; Birks, P., “Property and Unjust Enrichment: Categorical Truths” [1997] N.Z. Law Rev. 623Google Scholar; Birks, P., “The Law of Restitution at the End of an Epoch” (1999) 28 West. Aust. L.R. 13Google Scholar; P. Birks, “Property, Unjust Enrichment, and Tracing” (2001) 54 C.L.P. 231.

5 Grantham and Rickett, Enrichment and Restitution in New Zealand, chap. 3 and “Property and Unjust Enrichment: Categorical Truths or Unnecessary Complexity?” [1997] N.Z. Law Rev. 668.

6 [2001] 1 A.C. 102.

7 Birks, “Property, Unjust Enrichment, and Tracing”, at p. 234.

8 Virgo, op. cit., pp. 11-16.

9 Birks, “Property, Unjust Enrichment, and Tracing”, at p. 245; A. Burrows, “Proprietary Restitution: Unmasking Unjust Enrichment” (2001) 117 L.Q.R. 412; L. Smith, “Unjust Enrichment, Property, and the Structure of Trusts” (2000) 116 L.Q.R. 412; D. Fox, “Legal Title as Ground of Restitutionary Liability” [2000] R.L.R. 465; Swadling, W., “Property and Unjust Enrichment” in Harris, J.W. (ed.), Property Problems: From Genes to Pension Funds (London 1997)Google Scholar, chap. 11.

10 These influences can be seen in “Definition and Division: A Meditation on Institutes 3.13”; “Obligations: One Tier or Two?” in Stein, P.G. and Lewis, A.D.E. (eds.), Studies in Justinian's Institutes (London 1982)Google Scholar, chap. 3; “Introduction” in Birks, P. (ed.), English Private Law: Volume I (Oxford 2000)Google Scholar, xxxv. This is not to say that Birks’ taxonomy is entirely novel in the common law: see Fitzgerald, P.J., Salmond on Jurisprudence (12th edn., London 1966), 452Google Scholar.

11 See, principally, “Definition and Division: A Meditation on Institutes 3.13”; “Rights, Wrongs, and Remedies” (2000) 20 O.J.L.S. 1; “The Concept of a Civil Wrong” in Owen, D.G. (ed.), Philosophical Foundations of Tort Law (Oxford 1997)Google Scholar, chap. 1; “Equity in the Modern Law: An Exercise in Taxonomy” (1996) 26 West. Aust. L.R. 1.

12 Birks, “Obligations: One Tier or Two?”, at p. 20. The compensation may be payable either as a monetary equivalent to performance (Semelhago v. Paramadevan [1996] 2 S.C.R. 415) or, more commonly, as reparation for the loss caused by the wrong of non-performance.

13 Birks, “The Concept of a Civil Wrong”, at p. 48.

14 Unjust enrichment has been described as a central part of the law of obligations: Banque Financiere de la Cité v. Parc (Battersea) Ltd. [1999] 1 A.C. 221, 227 per Lord Steyn. See also Goff, Lord, “The Search for Principle”, most easily accessed in Swadling, W. and Jones, G.H. (eds.), The Search for Principle: Essays in Honour of Lord Goff of Chieveley (Oxford 1999)Google Scholar, Appendix at p. 324. However, the scope and extent of unjust enrichment is nevertheless much disputed.

15 See A. Beever, “The Structure of Aggravated and Exemplary Damages” (2003) 23 O.J.L.S. 87.

16 Generally, see P. Birks, “Rights, Wrong, Remedies” (2000) 20 O.J.L.S. 1; K. Barker, “Rescuing Remedialism in Unjust Enrichment Law: Why Remedies Are Right” [1998] C.L.J. 301; Evans, S., “Defending Discretionary Remedialism” (2001) 23 Sydney L.R. 463Google Scholar.

17 Although, in some cases the court's order may itself be the event. This is likely to be the case where the right is subject to strong curial discretion, as in the case of the remedial constructive trust: Fortex Group Ltd. (In Receivership and Liquidation) v. Macintosh [1998] 3 N.Z.L.R. 171 (C.A.).

18 We use these terms interchangeably in this paper.

19 Birks, “Property and Unjust Enrichment: Categorical Truths”; “Definition and Division: A Meditation on Institutes 3.13”.

20 Birks, “Property and Unjust Enrichment: Categorical Truths”, at p. 628.

21 Birks, P., “Unjust Enrichment and Wrongful Enrichment” (2001) 79 Texas L.R. 1767, 1788Google Scholar.

22 Birks, “Property, Unjust Enrichment, and Tracing” (2001) 54 C.L.P. 231, 245.

23 Birks, , “Private Law” in Birks, P. and Rose, F.D. (eds.), Lessons of the Swaps Litigation (London 2000)Google Scholar, chap. 1 at 7.

24 Birks, “Definition and Division: A Meditation on Institutes 3.13”, at p. 17.

25 Birks, “Unjust Enrichment and Wrongful Enrichment”, at p. 1779.

26 Ibid., p. 1778.

27 Birks, “The Concept of a Civil Wrong”, at p. 48.

28 Birks, “Property, Unjust Enrichment, and Tracing”, at p. 245.

29 Hospers, J., An Introduction to Philosophical Analysis (2nd edn., London 1970), 209Google Scholar.

30 For example, a right in rem may arise as a consequence of a contract for sale and purchase of an asset and the conveyance of title. In terms of the taxonomy, this is a species of the generic event of consent.

31 Birks, “Property and Unjust Enrichment: Categorical Truths”, at pp. 656-657.

32 Birks, “Property, Unjust Enrichment, and Tracing”, at p. 251; “Unjust Enrichment and Wrongful Enrichment”, at p. 1775. He locates this event in the fourth miscellaneous category.

33 See, for example, Burrows, “Proprietary Restitution: Unmasking Unjust Enrichment”; Smith, “Unjust Enrichment, Property, and the Structure of Trusts”; Swadling, , “Property and Unjust Enrichment”; Chambers, R., Resulting Trusts (Oxford 1997)Google Scholar, chap. 4; Edelman, J., Gain-Based Damages: Contract, Tort, Equity and Intellectual Property (Oxford 2001)Google Scholar, chap. 2; Fox, “Legal Title as a Ground for Restitutionary Liability”; M.P. McInnes, “Knowing Receipt and the Protection of Trust Property: Banton v. CIBC’ (2002) 81 Can. Bar. Rev. 171.

34 Virgo, Principles of the Law of Restitution, 15-17; Dietrich, J., Restitution (Sydney 1998)Google Scholar chap. 1.

35 Grantham and Rickett, Enrichment and Restitution in New Zealand, chap. 3.

36 The same need for interpretation also arises in determining whether a moral right-duty arises.

37 Birks, “Obligations: One Tier or Two?”, at pp. 20-21.

38 Sir Frederick Pollock's classic definition of a contract was a “promise or set of promises which the law will enforce”: Winfield, P., Pollock's Principles of Contract (13th edn., London 1950)Google Scholar, 1. See also B. Coote, “The Essence of Contract” (1988) 1 J. Contract Law 91; Atiyah, P.S., An Introduction to the Law of Contract (5th edn., Oxford 1995), 37-38Google Scholar; Treitel, G.H., “Contract” in Birks, (ed.), English Private Law: Volume II (Oxford 2000)Google Scholar, chap. 8 at p. 4.

39 Such is the degree to which the law concentrates on objective consent at the expense of the actual, subjective agreement of the parties that it is said to be possible for a contract to arise even though, subjectively, neither party intended to be bound: see Furness Withy (Australia) Pty. Ltd. v. Metal Distributors (U.K.) Ltd.: The Amazonia [1990] 1 Lloyds Rep. 236, 243 (C.A.).

40 Birks, “The Concept of a Civil Wrong”, at p. 48.

41 In common parlance “mistake” is a concept of wide import. It may suggest, on the one hand, an incorrect supposition that certain facts were true or that a certain state of affairs existed, while on the other hand, it may include a disappointed expectation or frustrated motivation. For the purposes of restitutionary recovery, however, “mistake” is defined more narrowly. Mistake is thus limited to a “supposition that a specific fact is true” (Kelly v. Solari (1841) 9 M. & W. 54, 58 per Parke B.) or that a certain state of affairs existed. Generally, see D. Sheehan, “What is a Mistake?” [2000] L.S. 538 and H. Dagan, “Mistakes” (2001) 79 Texas L.R. 1795. Moreover, until the recent decision of the House of Lords in Kleinwort Benson Ltd. v. Lincoln City Council [1999] 2 A.C. 349, a mistake of law did not support restitutionary recovery.

42 Birks, “Definition and Division: A Meditation on Institutes 3.13”, at pp. 25-26.

43 As an explanation of the creation of the right to restitution, however, this is deeply circular: the right to restitution arises in those circumstances in which the law says that there must be restitution. This nonetheless further highlights the crucial role of the legal characterisation of the facts in the generation of legal rights and duties.

44 Birks, “The Concept of a Civil Wrong”, at p. 37.

45 The idea of a sufficient causal link imports not only a chain of physical cause and effect, but also the satisfaction of the legal standard of causation, generally referred to in tort law as remoteness. See Rogers, W.V.H. Winfield and Jolowicz on Tort (15th edn., London 1998), 207Google Scholar.

46 Epstein, R., “The Ubiquity of the Benefit Principle” (1994) 67 Southern Cal. L.R. 1369Google Scholar; Rotherham, C., Proprietary Remedies in Context (Oxford 2002), 34Google Scholar; Harris, J.W., Property and Justice (Oxford 1996)Google Scholar, 3.

47 Hart, H.L.A. and Honore, A.M., Causation in the Law (2nd edn., Oxford 1985), 1618Google Scholar; Hospers, Introduction to Philosophical Analysis, 279-281.

48 This is true both of the creation of rights in personam and of rights in rem. There is no logical contradiction in the proposition that right in rem X can give rise to right in rem Y. Thus, as discussed below, the right in rem in an original asset may generate a new right in rem (if it is analytically necessary to conceive of it as a new right) in the traceable substitute of the original asset.

49 As perhaps occurred in Attorney General for Hong Kong v. Reid [1995] 1 A.C. 324. On one view, the Crown's equitable property rights in the assets acquired with the funds received by Reid arose because of Reid's breach of his fiduciary duties: see Rotherham, Proprietary Remedies in Context, 17, Alternatively, Reid may be seen as a case where the court gave effect to the intention of the parties as reflected in Reid's acceptance of his fiduciary duties. On this basis, the Crown's equitable property rights arise as a legal (though not necessarily real) implication of the fiduciary duty. See Grantham and Rickett, Enrichment and Restitution in New Zealand, 409.

50 See, for a potential example, Chase Manhattan Bank N.A. Ltd. v. Israel-British Bank (London) Ltd. [1981] Ch. 105.

51 The view that rights in rem are only ever a response also seems incapable of explaining how rights arise in an asset that has not previously been owned. Thus, a fisherman who catches a fish from the ocean becomes the owner of the fish, but it is difficult to see to what event (other than by yet a further addition to the rather overworked rubbish bin of the miscellaneous fourth category) that right in rem is a response.

52 Once in existence, however, a right in rem may then generate further rights in rem.

53 This distinction may also be described in terms of exigibility: from whom may the right be demanded? See Birks, P., An Introduction to the Law of Restitution (Oxford 1985), 4950Google Scholar; Penner, J., The Idea of Property in Law (Oxford 1997), 31Google Scholar. Rights in personam are exigible against a specific individual, while rights in rem are exigible against an indefinite class of persons.

54 Fundamental Legal Conceptions as Applied in Judicial Reasoning (New Haven, 1919).

55 Generally, see Harris, Property and Justice, 120-125; P. Eleftheriadis, “The Analysis of Property Rights” (1996) 16 O.J.L.S. 31.

56 Hohfeld made this distinction through the concepts of “multital” rights (rights in rem) and “paucital” rights (rights in personam): Fundamental Legal Conceptions, 72.

57 Birks, P., “Before We Begin: Five Keys to Land Law” in Bright, S. and Dewar, J. (eds.), Land Law: Themes and Perspectives (Oxford 1998)Google Scholar, chap. 18 at p. 473; J. Penner, “The ‘Bundle of Rights’ Picture of Property” (1996) 43 U.C.L.A.L.R. 711; Harris, Property and Justice, 120—125.

58 Hohfeld identified the difference as being “extrinsic” to the nature of the right itself. Beyond this, however, he was not able to explain what makes a multital right multital. See Eleftheriadis, “The Analysis of Property Rights”, at pp. 46-47; Honore, A.M., “Rights of Exclusion and Immunities Against Divesting” (1960) 34 Tulane L.R. 453Google Scholar.

59 Generally, see Penner, The Idea of Property in Law, 23-31.

60 Ibid., p. 24. See also Smith, L., The Law of Tracing (Oxford 1997), 5051Google Scholar.

61 Ibid., p. 29.

62 Fitzgerald, Salmond on Jurisprudence, 244.

63 The Idea of Property in Law, 24.

64 Noyes, C.R., The Institution of Property (New York 1936), 241Google Scholar.

65 Penner, The Idea of Property in Law, 31.

66 Westdeutsche Landesbank Girozentrale v. Islington London Borough Council [1996] A.C. 669, 707 per Lord Browne-Wilkinson. See also Birks, “Property and Unjust Enrichment: Categorical Truths”, at p. 650; P. Birks, “Personal Property: Proprietary Rights and Remedies” (2000) 11 King's College L.J. 1, 4-5; McInnes, “Knowing Receipt and the Protection of Trust Property: Banton v. CIBC”, at pp. 176-177.

67 [1996] 1 W.L.R. 387 (C.A.).

68 Nicholas, B., An Introduction to Roman Law (Oxford 1962) 125128Google Scholar; Buckland, W.W., A Textbook of Roman Law from Augustus to Justinian (3rd edn. rev. by Stein, P.G., Cambridge 1963), 675Google Scholar; Schulz, F., Classical Roman Law (Oxford 1951), 368372Google Scholar.

69 Birks, “Property and Unjust Enrichment: Categorical Truths”, at p. 656; “Property, Unjust Enrichment, and Tracing”, at p. 250.

70 Birks, “Rights, Wrongs, Remedies”, at p. 15.

71 It is important not to infer from the pecuniary nature of the award that the award is in response to some wrongdoing. It is perfectly rational for a system of law to convert all obligations into pecuniary form at the point of judgment. In Roman law, this was referred to as the principle of condemnatio pecuniaria. See Jolowicz, H.F. and Nicholas, B., Historical Introduction to the Study of Roman Law (3rd edn., Cambridge 1972), 204205, 213-214Google Scholar.

72 This is manifested in the definition of those entitled to bring a claim in conversion in terms of those with either actual possession or the right to possess. Possession is central to the common law concept of title to chattels. Generally, see Honore, A.M., “Ownership” in Guest, A.G. (ed.), Oxford Essays in Jurisprudence (Oxford 1961), at p. 113Google Scholar; Rose, C.M., “Possession as the Origin of Property” (1985-1986) 52 Univ. Chicago L.R. 73Google Scholar.

73 J A Pye (Oxford) Ltd. v. Graham [2003] 1 A.C. 419. Indeed, in some circumstances possession becomes a property right good against all including the rightful owner.

74 (1772) 1 Strange 505. Generally, see Rogers, Winfield and Jolowicz on Tort (15th edn.), 600; Dugdale, A.M., Clerk & Lindsell on Torts (18th edn., London 2000), 749Google Scholar.

75 Birks, “Property and Unjust Enrichment: Categorical Truths”, at p. 657; “Property, Unjust Enrichment, and Tracing”, at p. 251; “Unjust Enrichment and Wrongful Enrichment”, at p. 1775.

76 Birks, “Property, Unjust Enrichment, and Tracing”, at p. 245.

77 [1996] 3 All E.R. 747, 758.

78 There is an important analytical distinction between the possibility of analysing the claimant's case as one for redress for a wrong and the necessity of doing so. In cases where the law will give effect directly to the primary right, there is no need for a wrongs analysis. Perhaps the clearest example of this is the case of contract. The right to specific performance is not a response to the wrong of breach of contract, but is the fulfilment of the right to performance. Thus, specific performance is available where there is no breach: Hashiam v. Zenab [1960] A.C. 316 (P.C.). See also Semelhago v. Paramadevan [1996] 2 S.C.R. 415 (performance secured by an award of money as a substitute).

79 Birks, “Property and Unjust Enrichment: Categorical Truths”, at p. 657; “Property, Unjust Enrichment, and Tracing”, at p. 251.

80 In re Eastgate [1905] 1 K.B. 465; Tilley v. Bowman [1910] 1 K.B. 745.

81 Birks, “Property and Unjust Enrichment: Categorical Truths”, at pp. 657-658.

82 [2001] 1 A.C. 102. Birks acknowledges this in “Property, Unjust Enrichment, and Tracing”, and in “Receipt” in Birks, P. and Pretto, A. (eds.), Breach of Trust (Oxford 2002), at pp. 216–217Google Scholar.

83 Ibid, p. 108.

84 Baker, J.H., An Introduction to English Legal History (4th edn., London 2002), 5759Google Scholar; Milsom, S.F.C., Historical Foundations of the Common Law (2nd edn., London 1981), 243246Google Scholar, 269-275; Ibbetson, D.J., A Historical Introduction to the Law of Obligations (Oxford 1999), 107108Google Scholar; A.W.B. Simpson, “The Introduction of the Action on the Case for Conversion” (1959) 75 L.Q.R. 864.

85 Milsom, op. cit., 270. There is a fundamental cleavage in the common law between claims demanding performance of a right and those seeking redress for a wrong. Historically, this was reflected in the distinction between actions founded on a praecipe writ and those founded on a plaint. This distinction is said to be Germanic in origin: Pollock, F. and Maitland, F.W., The History of English Law (2nd edn., Cambridge 1968) vol. 2, 571Google Scholar.

86 Baker, Introduction to English Legal History, 399; Rogers, Winfield and Jolowicz on Tort (15th edn.), 583-585.

87 The Torts (Interference with Goods) Act 1977, s. 2, abolished detinue and extended conversion to those cases that detinue did not reach. See Dugdale, Clerk & Lindsell on Torts, 728.

88 While they are the most well understood, torts are not the only form of indirect enforcement of common law property rights. In particular, the actions in money had and received and debt may serve to vindicate property rights in money (see Goff and Jones, The Law of Restitution, 3-4, 96-103; Holiday v. Sigil (1826) 2 Car. & P. 176). The English Court of Appeal's decision in Trustee of Jones v. Jones [1997] Ch. 159 illustrates this. Money was transferred from the account of the plaintiff trustee to Mrs. Jones, who had no right to it. Mrs. Jones speculated with the money and multiplied it several times. She deposited the sum in an account specially opened for that purpose. The plaintiff sought recovery of all the funds thus deposited. The Court was clearly of the view that the plaintiff was simply seeking to protect his property rights and that the medium of this protection was the action in debt (or possibly money had and received).

Their Lordships’ emphasis in Lipkin Gorman (a firm) v. Karpnale Ltd. [1991] 2 A.C. 548, on the plaintiff's title to the money as the foundation of the claim in money had and received also suggests that the event in respect of which the in personam right to restitution arose was property (see Swadling, W., “Restitution and Bona Fide Purchase” in Swadling, W. (ed.), The Limits of Restitutionary Claims: A Comparative Analysis (London 1997)Google Scholar chap. 4 at pp. 97ff; Virgo, G.J., “What is the Law of Restitution About?” in Cornish, W., Nolan, R., O’Sullivan, J. and Virgo, G.J. (eds.), Restitution: Past, Present and Future (Oxford 1998), chap. 20, at pp. 313-314Google Scholar; Box v. Barclays Bank pic. [1998] Lloyd's Rep. Bank 185.

89 Thus, conversion is often described as a proprietary action: Baker, Introduction to English Legal History, 399; Fleming, J., The Law of Torts (9th edn., Sydney 1998), 61Google Scholar.

90 Hartop v. Hoare (1743) 2 Str. 1187; Cooper v. Chitty (1756) 1 Burr. 20. See also Baker, J.H. and Milsom, S.F.C., Sources of English Legal History (London 1986), 583584Google Scholar. The point here is that while there will always be some “wrongdoing” in the sense that the defendant has interfered with a right of the plaintiff, analytically the basis of the claim is no longer the defendant's fault or culpability.

91 (1705) 6 Mod. 212.

92 [2002] 2 W.L.R. 1353. Lord Nicholls (at p. 1375) briefly considered the suggestion that the claim in conversion might be analysed in terms of the principle of unjust enrichment. It is clear, however, from his Lordship's characterisation of this suggestion as a “radical reappraisal” that he did not regard this as the nature of the tort at the present time.

93 Ibid., p. 1388. Generally, see Weir, T., Tort Law (Oxford 2002)Google Scholar, chap. 11.

94 Birks, “Personal Property: Proprietary Rights and Remedies”, at p. 7.

95 Smith, Law of Tracing, 285.

96 Birks, “The Concept of a Civil Wrong”.

97 Weir, Tort Law, 126.

98 Smith, Law of Tracing, 52.

99 Penner, The Idea of Property in Law, 128-152; Honore, “Ownership”, 119-120. Harris, Property and Justice, 24, 86-90, refers to this as the non-trespass rule.

100 Birks, “Unjust Enrichment and Wrongful Enrichment”, at p. 1775.

101 While somewhat convoluted, there is nothing illogical in the indirect enforcement of rights in rem. The nature of the right and the means of protecting and enforcing the right are distinct issues. See Smith, Law of Tracing, 59-60.

102 (1841) 8 M. & W. 540, 550.

103 [1962] 1 Q.B. 701.

104 Birks, “Equity in the Modern Law: An Exercise in Taxonomy”, at p. 16.

105 These examples are taken from Birks, ibid., at p. 6.

106 Birks, “The Concept of a Civil Wrong”, at p. 51.

107 In English law, the concept of unjust enrichment does not of itself articulate a standard of justiciability. The principle of “unjust enrichment” is thus merely a descriptive label that looks downward to the cases to divine its content. In this respect, although recent academic analyses have sought to add further categories of “unjustness”, the list of factors recognised in the authorities has not changed greatly from the list proposed by Lord Mansfield in Moses v. Macferlan (1760) 2 Burr. 1005, 1012: “… money paid by mistake; or upon a consideration which happens to fail; or for money got through imposition, (express, or implied;) or extortion; or oppression; or an undue advantage taken of the plaintiff's situation, contrary to laws made for the protection of persons under those circumstances”. The justification for the restoration of the status quo ante inherent in these circumstances is that the plaintiff did not subjectively consent to the enrichment of the defendant. Whether manifested in the denial of legal capacity to minors and juristic persons, or the presence of mistake, coercion, or morbid dependence on the defendant, it is the defect in the plaintiff's subjective consent that identifies the transfer of wealth as one that, if not reversed, would unjustly enrich the defendant.

108 Ilich v. R. (1987) 162 C.L.R. 110; Portman Building Society v. Hamlyn Taylor Neck (a firm) [1998] 4 All E.R. 202.

109 R. Grantham and C.E.F. Rickett, “On the Subsidiarity of Unjust Enrichment” (2001) 117 L.Q.R 273.

110 Nicholas, B., “Modern Developments in the French Law of Unjustified Enrichment” in Russell, P. (ed.), Unjustified Enrichment: A Comparative Study of the Law of Restitution (Amsterdam 1996), 77, 94Google Scholar, speaking in the context of French law, says: “Windscheid's formulation does, however, point to the fundamental limit on any enrichment remedy—that it must not circumvent an existing rule or law which envisages the relevant aspect of the matter in issue. It must not perpetrate a fraud on the law”.

111 Virgo, Principles of the Law of Restitution, 41. This is also true of the German law of unjustified enrichment: see Markesinis, B.S., Lorenz, W. and Dannemann, G., The German Law of Obligations (Oxford 1997), vol. 1, p. 43Google Scholar.

112 Pan Ocean Shipping Ltd. v. Creditcorp Ltd.: The Trident Beauty [1994] 1 W.L.R. 161, 164 per Lord Goff. See also Stocznia Gdanska S.A. v. Latvian Shipping Co. [1998] 1 W.L.R. 574 (H.L.), where it was held that the contract itself dealt with the consequences of rescission of the contract.

113 See further, Grantham and Rickett, Enrichment and Restitution in New Zealand, chap. 3.

114 Honore, “Ownership”.

115 In Portman Building Society v. Hamlyn Taylor Neck (a firm) [1998] 4 All E.R. 202, the Court of Appeal rejected the notion that a purely factual enrichment would suffice for this purpose.

116 Generally, see Grantham and Rickett, “On the Subsidiarity of Unjust Enrichment”.

117 Moses v. Macferlan (1760) 2 Burr. 1005, 1012; Fibrosa Spolka Akcyjna v. Fairbairn Lawson Combe Barbour Ltd. [1943] A.C. 32, 61; Dollar Land (Cumbernauld) Ltd. v. CIN Properties Ltd. [1998] 3 E.G.L.R. 79 (H.L.); Banque Financière de la Cité v. Parc (Battersea) Ltd. [1999] 1 A.C. 221, 231.

118 Pan Ocean Shipping Ltd. v. Creditcorp Ltd.: The Trident Beauty [1994] 1 W.L.R. 161, 164 per Lord Goff.

119 Fleming, Law of Torts, 61; W.L. Prosser, “Nature of Conversion” (1957) 42 Cornell L.Q. 168; Warren, E.H., “Qualifying as Claimant in an Action for Conversion” (1936) 49 Harv. L.R. 1084Google Scholar.

120 Birks, “Property and Unjust Enrichment: Categorical Truths”, at pp. 645-650.

121 Birks, ibid., p. 661. See also P. Birks, “Establishing a Proprietary Base” [1995] R.L.R. 83, 91; P. Birks, “On Taking Seriously the Difference Between Tracing and Claiming” (1997) 11 Trust Law Int. 2, 7-8; Smith, Law of Tracing, 299-301; Rotherham, C., “The Metaphysics of Tracing: Substituted Title and Property Rhetoric” (1996) 34 Osgoode Hall L.J. 321Google Scholar; Worthington, S., “Justifying Claims to Secondary Profits” in Schrage, E.J.H. (ed.), Unjust Enrichment and the Law of Contract (London 2001), 451, 463-464Google Scholar.

122 Ibid..

123 [2001] 1 A.C. 102.

124 Birks, “Property and Unjust Enrichment: Categorical Truths”, at pp. 646-657.

125 In Foskett, the claimant's could not have made out a claim unjust enrichment. Their Lordships (without dissent on this point) found that the defendants were not enriched by the plaintiffs’ value and, being innocent donees, there was no unjust factor that could be asserted against them.

126 [1991] 2 A.C. 548.

127 [1997] Ch. 159 (C.A.).

128 [1991] 2 A.C. 548, 573.

129 While it was clear that trust money was used to pay the fourth and fifth premiums, there was some doubt as the provenance of the money used to pay the third premium.

130 [2001] 1 A.C. 102, 109.

131 “Absolute” was used by Lord Browne-Wilkinson to indicate that no discretion was involved.

132 [2001] 1 A.C. 102, 127.

133 Ibid..

134 Ibid..

135 Birks, “Property, Unjust Enrichment, and Tracing”, at pp. 244-245; Burrows, “Proprietary Restitution: Unmasking Unjust Enrichment”, at p. 418.

136 Rotherham, Proprietary Remedies in Context, 98; Worthington, “Justifying Claims to Secondary Profits”, at pp. 463-464; Birks, “Property, Unjust Enrichment, and Tracing”, at p. 244.

137 Generally, see G. Samuel, “Can Gaius Really be Compared to Darwin?” (2000) 49 I.C.L.Q. 297; K. Gray, “Property in Thin Air” [1991] C.L.J. 252; Cotterrell, R., “The Law of Property and Legal Theory” in Twining, W. (ed.), Legal Theory and Common Law (Oxford 1987)Google Scholar, Ch. 5; C. Rotherham, “Conceptions of Property in Common Law Discourse” (1998) 18 L.S. 41.

138 Generally, see C. Harpum, “Overreaching, Trustees’ Powers and the Reform of the 1925 Legislation” [1990] C.L.J. 277; D. Fox, “Overreaching” in Birks and Pretto (eds.), Breach of Trust, chap. 4; R. Nolan, ‘‘Vandervell v. I.R.C.: A Case of Overreaching” [2002] C.L.J 169.

139 Law of Property Act 1925, s. 53(1)(c), requires all dispositions of equitable interests to be in writing.

140 Nolan, ‘‘Vandervell v. I.R.C.: A Case of Overreaching”.

141 [2001] 1 A.C. 102, 130.

142 There may be an analogy here with notions of ratification: Re Hallett's Estate (1880) 13 Ch. D. 696, 708-709; Rotherham, Proprietary Remedies in Context, 94.

143 Epstein, R., “A Clear View of The Cathedral: The Dominance of Property Rules” (1997) 106 Yale L.J. 2091Google Scholar, 2097; Rotherham, C., “Property and Justice” in Kramer, M. (ed.), Rights, Wrongs and Responsibilities (London 2001)Google Scholar, chap. 5. Blackstone, Commentaries on the Laws of England (1st edn., 1766) Book 2, p. 8, made the point thus: “Necessity begat property, and, in order to insure that property, recourse was had to civil society,…”See also the comments of Lord Camden in Entick v. Carrington (1765) 2 Wils. 275, 291: “the great end for which men entered society was to preserve their property. That right is preserved sacred and incommunicable…”

144 See Samuel, G., “The Many Dimensions of Property” in Maclean, J. (ed.), Property and the Constitution (Oxford 1999)Google Scholar, chap. 3.

145 Cf., JA Pye (Oxford) Ltd. v. Graham [2003] 1 A.C. 419.