¹ McInnes, M., “‘At the Plaintiff's Expense’: Restitutionary Relief” [1998] C.L.J. 472 Google Scholar. Following his example, this article uses male pronouns for claimants and female pronouns for defendants when speaking in the abstract.

² See the reference to double plafond in French law: Linssen, S., “Remedies for Wrongdoing: The Measure of Recovery” (2006) 14 E.R.P.L. 351, 357Google Scholar.

³ Nortje v Pool N.O. 1966 3 S.A. 96 (A), 104.

⁴ Pettkus v Becker [1980] 2 S.C.R. 217, 227; Cie Immobilière Viger Ltée v Laurgat Giguère Inc. [1977] 2 S.C.R. 67, 77.

⁵ McInnes, “‘At the Plaintiff's Expense’”, p. 473, referring to the “growing body of opinion” to the contrary including Birks, P., “Definition and Division: A Mediation on Institutes 3.13” in Birks, P. (ed.) The Classification of Obligations (Oxford 1997) 1, 26Google Scholar.

⁶ TFL Management Ltd. v Lloyds TSB Bank plc [2013] EWCA Civ 1415; [2014] 1 W.L.R. 2006, at [86].

⁷ Benedetti v Sawiris [2013] UKSC 50; [2014] A.C. 938, at [21]; cf. at [100]–[109], [119].

⁸ Banque Financière de la Cité v Parc (Battersea) Ltd. [1999] 1 A.C. 221, 227, 234.

⁹ Filby v Mortgage Express (No. 2) Ltd. [2004] EWCA Civ 759; [2004] N.P.C. 98; Relfo Ltd. (In Liquidation) v Varsani [2014] EWCA Civ 360; [2015] 1 B.C.L.C. 14; Menelaou v Bank of Cyprus plc [2015] UKSC 66; [2016] A.C. 176.

¹⁰ See e.g. MacDonald Dickens & Macklin v Costello [2011] EWCA Civ 930; [2012] Q.B. 244.

¹¹ Birks, P., An Introduction to the Law of Restitution (Oxford 1985), 133–34Google Scholar; Arris v Stukely (1677) 2 Mod. 660; 86 E.R. 1060; King v Alson (1848) 12 Q.B. 971; 116 E.R. 1134.

¹² This is the example used in McInnes, “‘At the Plaintiff's Expense’”, 472. See also Greenwood v Bennett [1973] Q.B. 195, where the claimant was awarded only the £226 the repairs “cost him [in] labour and material”: at 200.

¹³ This is the inverse of the situation in Sempra Metals v IRC [2007] UKHL 34; [2008] 1 A.C. 561.

¹⁴ This assumes that Sempra Metals [2007] UKHL 34; [2008] 1 A.C. 561 is correctly decided and puts to one side the question whether the “use value” of the money is something that was transferred from the claimant.

¹⁵ This is a variation (to exclude proprietary remedies) of the example used by Grantham, R. and Rickett, C., “Disgorgement for Unjust Enrichment?” [2003] C.L.J. 159, 165CrossRefGoogle Scholar.

¹⁶ These are the facts of Trustee of Jones v Jones [1997] Ch. 159, except that, in that case, the money came to the hands of the defendant by transfer in breach of trust, leading the court and most commentators to characterise the case as one involving the “vindication of property rights”: see e.g. Grantham and Rickett, “Disgorgement for Unjust Enrichment?”, 171. Let us assume for these purposes that a proprietary remedy does not (necessarily) follow upon a mistaken payment: e.g. Salmons, D., “The Availability of Proprietary Restitution in Cases of Mistaken Payments” (2015) 74 C.L.J. 534 CrossRefGoogle Scholar; cf. Chase Manhattan Bank N.A. v Israel-British Bank (London) Ltd. [1981] Ch. 105.

¹⁷ Greiss, J., “Causes of Action Supporting a Constructive Trust” (2011) 38 Advocacy Quarterly 249, 254–55Google Scholar.

¹⁸ That is, in circumstances not constituting mitigation: e.g. Gardner v Marsh & Parsons [1997] 1 W.L.R. 489; Needler Financial Services v Taber [2002] Lloyd's Rep. 32.

¹⁹ Duggan, A., “Constructive Trusts from a Law and Economics Perspective” (2005) 55 U.T.L.J. 217, 227CrossRefGoogle Scholar.

²⁰ Kelly v Solari (1841) 9 M. & W. 54, 58–59.

²¹ See e.g. Kleinwort Benson Ltd. v Lincoln City Council [1999] A.C. 349, 406, per Lord Hope; Peel (Regional Municipality) v Ontario [1992] 3 S.C.R. 762, 788, per McLachlin J.; Weinrib, E., “The Normative Structure of Unjust Enrichment” in Rickett, C. and Grantham, R. (eds.), Structure and Justification in Private Law: Essays for Peter Birks (Oxford 2008), 21 Google Scholar.

²² E.g. Lodder v Slowey [1904] A.C. 442; Boomer v Muir 24 P. 2d 570, 574 (Cal. App. 1933); Friedmann, D., “Does the Dead Contract Rule Restitution from Its Grave?” (2012) 92 B.U.L.Rev. 811 Google Scholar; cf. Taylor v Motability Finance Ltd. [2004] EWHC 2619 (Comm).

²³ See Test Claimants in the FII Group Litigation v HMRC [2008] EWHC 2893 (Ch); [2009] S.T.C. 254, at [342].

²⁴ Roxborough v Rothmans of Pall Mall Australia Ltd. [2001] HCA 68; (2001) 208 C.L.R. 516; Pitt v Holt [2013] UKSC 26; [2013] 2 A.C. 108, at [124]–[125].

²⁵ Grantham, R., “Restitutionary Recovery Ex Aequo et Bono” [2002] Sing. J.L.S. 388, 402Google Scholar; see also p. 397, lamenting the “general attachment in Australian law to the notion of unconscionability as a solvent of legal problems”.

²⁶ Grantham and Rickett, “Disgorgement for Unjust Enrichment?”, 162–63; Smith, S., “Justifying the Law of Unjust Enrichment” (2001) 79 Tex.L.Rev. 2177 Google Scholar.

²⁷ Grantham and Rickett, “Disgorgement for Unjust Enrichment?”, 159.

²⁸ Air Canada v British Columbia [1989] 1 S.C.R. 1161, 1202. See also Roxborough [2001] HCA 68; (2001) 208 C.L.R. 516, at [119]–[120], [125]–[144], per Kirby J. (dissenting); Banque Financire de la Cité [1999] 1 A.C. 221, 237, per Lord Clyde; Citadel General Assurance Co. v Lloyds Bank Canada [1997] 3 S.C.R. 805, 824, per La Forest J.

²⁹ The term “correspondence” ( Burrows, A., The Law of Restitution (Oxford, 2011), 64 Google Scholar; Grantham and Rickett, “Disgorgement for Unjust Enrichment?”, 166) is deliberately avoided so as not to imply that the claimant's loss and defendant's gain need be identical: e.g. in Sempra Metals [2007] UKHL 34; [2008] 1 A.C. 561, it could be no objection that the defendant's gain was (presumably) less than the claimant's loss.

³⁰ This view finds some support in the reasons of Lord Neuberger in Benedetti [2013] UKSC 50; [2014] A.C. 938, at [197].

³¹ Burrows, Law of Restitution, 110.

³² E.g. MacDonald Dickens & Macklin [2011] EWCA Civ 930; [2012] Q.B. 244; Uren v First National Home Finance Ltd. [2005] EWHC 2529 (Ch); [2005] All E.R. (D) 146; Brown and Davis v Galbraith [1972] 1 W.L.R. 997.

³³ See note 12 above and accompanying text.

³⁴ Grantham and Rickett, “Disgorgement for Unjust Enrichment?”, 166–67.

³⁵ This is a variation of Roxborough [2001] HCA 68; (2001) 208 C.L.R. 516 and Kleinwort Benson Ltd. v Birmingham City Council [1997] Q.B. 380. See further below, Section II(B)(1).

³⁶ Woodward, W., “Passing On the Right to Restitution” (1985) 39 U.Miami L.Rev. 873 Google Scholar; Jones, G., Restitution in Public and Private Law (London 1991), 28–37, 46–47Google Scholar.

³⁷ Particularly in civil law systems: see Rudden, B. and Bishop, W., “ Gritz and Quellmehl: Pass it On” (1981) 6 E.L.Rev. 243 Google Scholar.

³⁸ Kleinwort Benson Ltd. [1997] Q.B. 380, 744; Kleinwort Benson Ltd. v South Tyneside Metropolitan Borough Council [1994] 4 All E.R. 972.

³⁹ Roxborough [2001] HCA 68; (2001) 208 C.L.R. 516.

⁴⁰ Ibid., at pp. 354–55.

⁴¹ Grantham, “Restitutionary Recovery”, 389; Burrows, A., “The Australian Law of Restitution: Has the High Court Lost Its Way?” in Bant, E. and Harding, M. (eds), Exploring Private Law (Cambridge 2010), 67–85 CrossRefGoogle Scholar.

⁴² Commissioner of State Revenue (Victoria) v Royal Insurance Australia Ltd. [1994] HCA 61; (1994) 182 C.L.R. 51, 90.

⁴³ Woolwich Equitable Building Society v IRC (No. 2) [1993] A.C. 70, 177–178; Roxborough [2001] HCA 68; (2001) 208 C.L.R. 516, at [119]–[120], [125]–[144].

⁴⁴ Kingstreet Investments Ltd. v New Brunswick (Department of Finance) 2007 SCC 1; [2007] 1 S.C.R. 3; cf. Air Canada [1989] 1 SCR 1161, 1202; Kerr v Baranow 2011 SCC 10, (2011) 328 D.L.R. (4th) 577, at [39].

⁴⁵ Alder, J., “Restitution in Public Law: Bearing the Cost of Unlawful State Action” (2002) L.S. 165 Google Scholar.

⁴⁶ Williams, R., Unjust Enrichment and Public Law: A Comparative Study of England, France and the EU (London 2010), 31–40 Google Scholar.

⁴⁷ Bant, E., “Restitution from the Revenue and Change of Position” [2009] L.M.C.L.Q. 166, 172Google Scholar, cited with approval in Test Claimants in the FII Group Litigation v HMRC (No. 2) [2014] EWHC 4302 (Ch); [2015] S.T.C. 1471, at [310].

⁴⁸ The view of such defendants as “wrongdoers” was disavowed in Test Claimants in the FII Group Litigation [2014] EWHC 4302 (Ch); [2015] S.T.C. 1471, at [309]–[315].

⁴⁹ M. McInnes, “A Return to First Principles in Unjust Enrichment: Kerr v Baranow” (2011) 51 Canada Business Law Journal 275, 282. In competition law, lost sales may themselves be claimed as recoverable loss, but are not inconsistent with an adjusted passing-on defence except in a monopoly or wholly cartelised market: Verboven, F. and van Dijk, T., “Cartel Damages Claims and the Passing-On Defence” (2009) 57 Journal of Industrial Economics 457, 465–66Google Scholar. See further below, text accompanying notes 59–67.

⁵⁰ Kleinwort Benson Ltd. [1994] 4 All E.R. 972.

⁵¹ Virgo, G., The Principles of the Law of Restitution (Oxford 1999), 739 Google Scholar.

⁵² Grantham and Rickett, “Disgorgement for Unjust Enrichment?”, 169.

⁵³ McInnes, M., “The Canadian Principle of Unjust Enrichment: Comparative Insights into the Law of Restitution” (1999) 27 Alta.L.Rev. 1, 23Google Scholar.

⁵⁴ That is, to the extent that she is not disqualified from the defence by bad faith or wrongdoing: e.g. Lipkin Gorman (a firm) v Karpnale Ltd. [1990] 1 A.C. 548, 580.

⁵⁵ This notion of imbalance is evident in the cases establishing the change of position defence: ibid., at p. 579; see also David Securities Pty. Ltd. v Commonwealth Bank of Australia [1992] HCA 48; (1992) 175 C.L.R. 353, 385.

⁵⁶ Some authors suggest that the change of position defence is itself broad enough to cover both disenrichment of the defendant and reduction in the claimant's loss: see Grantham and Rickett, “Disgorgement for Unjust Enrichment?”, 177. It is not necessary to go that far, as the defence of passing on is analytically distinct in that it negatives a different element of the action and requires proof of different matters.

⁵⁷ Lipkin Gorman (a firm) [1991] 2 A.C. 548, 560, per Lord Templeman.

⁵⁸ Scottish Equitable plc v Derby [2000] 3 All E.R. 793, at [44]; cf. Australia and New Zealand Banking Group Ltd. v Westpac Banking Corporation [1988] HCA 17; (1988) 164 C.L.R. 662, 677–78.

⁵⁹ Competition Act 1998, s. 36.

⁶⁰ See above, text accompanying notes 17–28.

⁶¹ See Hanover Shoe Inc. v United Shoe Machinery Corporation, 392 US 481, 491–94 (1968).

⁶² See Case C-453/99, Courage Ltd. v Crehan [2002] Q.B. 507; Case 68/79, Hans Just I/S v Danish Ministry for Fiscal Affairs [1981] 2 C.M.L.R. 714, at [20]; see also Parliament and Council Directive (EU) No 2014/104 (OJ L 349, p. 1) (Damages Directive), Article 14.

⁶³ Devenish Nutrition Ltd. v Sanofi-Aventis S.A. [2008] EWCA Civ 1086; [2009] Ch. 390, at [147], [151]; Emerald Supplies Ltd. v British Airways plc [2009] EWHC 741(Ch); [2010] Ch. 48, at [37]; WH Newson Holding Ltd. v IMI plc [2013] EWCA Civ 1377; [2014] 1 All E.R. 1132, at [40].

⁶⁴ Sainsbury's Supermarkets v Mastercard Inc. [2016] CAT 11.

⁶⁵ Ibid., at para. [484].

⁶⁶ See Fulton Shipping Inc. v Globalia Business Travel S.A.U. [2014] EWHC 1547 (Comm), at [17]; T. Jones, “The English Law of Causation and the Passing-On Defence”, Blackstone Chambers Competition Law Bulletin (online), 30 June 2014.

⁶⁷ See the submissions of Thomas de la Mare Q.C. in Devenish Nutrition Ltd. [2008] EWCA Civ 1086; [2009] Ch. 390, 433–34, 443 [31].

⁶⁸ E.g. Foskett v McKeown [2001] 1 A.C. 102; Re Diplock [1951] A.C. 251.

⁶⁹ Foskett [2001] 1 A.C. 102, 115; see Virgo, The Principles, 559.

⁷⁰ Chambers, R., “Two Kinds of Enrichment”, in Chambers, R., Mitchell, C. and Penner, J. (eds.), Philosophical Foundations of the Law of Unjust Enrichment (Oxford 2009), 258 CrossRefGoogle Scholar.

⁷¹ Ibid., at p. 267.

⁷² Consider e.g. Ministry of Defence v Ashman (1993) 25 H.L.R. 513; Shi v Jiangsu Native Produce Import & Export Corp [2009] EWCA Civ 1582, at [18]–[28]; Strand Electric and Engineering Co. Ltd. v Brisford Entertainments Ltd. [1952] 2 Q.B. 246.

⁷³ Edwards v Lees Administrators 96 S.W. 2d 1028 (Ky. 1936).

⁷⁴ Birks, P., “‘At the Expense of the Claimant’: Direct and Indirect Enrichment in English Law” in Johnson, D. and Zimmermann, R. (eds.), Unjustified Enrichment: Key Issues in Comparative Perspective (Cambridge 2002), 510 Google Scholar. Birks also characterises it as one of interceptive subtraction.

⁷⁵ Jackman, I., “Restitution for Wrongs” [1989] C.L.J. 302, 308CrossRefGoogle Scholar. Note that others consider that a remedy should flow automatically from interference with property rights: see Grantham and Rickett, “Disgorgement for Unjust Enrichment?”, 174.

⁷⁶ Strand Electric and Engineering Co. Ltd. [1952] 2 Q.B. 246.

⁷⁷ The Mediana [1900] A.C. 113, 117.

⁷⁸ Watson Laidlaw & Co. Ltd. v Pott Cassels & Williamson (1914) 31 R.P.C. 104, 119.

⁷⁹ Sempra Metals [2007] UKHL 34; [2008] 1 A.C. 561, at [116].

⁸⁰ Watson Laidlaw & Co. Ltd. (1914) 31 R.P.C. 104, 118–19.

⁸¹ See e.g. Attorney General v Blake [2001] 1 A.C. 268, 278–79; Devenish Nutrition Ltd. [2008] EWCA Civ 1086; [2009] Ch. 390, 449 [51].

⁸² Wrotham Park Estate Co. Ltd. v Parkside Homes Ltd. [1974] 1 W.L.R. 798.

⁸³ Regal (Hastings) Ltd. v Gulliver [1967] 2 A.C. 134.

⁸⁴ Kelly (1841) 9 M. & W. 54, 59.

⁸⁵ Although in Dimond v Lovell [2002] 1 A.C. 384 there was no inquiry into whether the car would otherwise have been hired, the claimant company was in the business of doing so and it could not have been easily assumed that it suffered no loss. The question was not raised for consideration and the observations on enrichment were brief and obiter: at 397–98.

⁸⁶ Brenner v First Artists’ Management Pty. Ltd. [1993] 2 V.R. 221, 262.

⁸⁷ Burrows, Law of Restitution, 64.

⁸⁸ Edelman, J. and Bant, E., Unjust Enrichment in Australia (2006), 123 Google Scholar.

⁸⁹ Philip Collins Ltd. v Davis [2000] 3 All E.R. 808; Scottish Equitable plc [2000] 3 All E.R. 793.

⁹⁰ Consider e.g. the witness statement the innocent defendant was forced to give in Scottish Equitable plc [2000] 3 All E.R. 793, at [16]. While proof of a large mistaken payment may be very easily achieved, the same cannot be said of particularisation of a change of position.

⁹¹ See above, text accompanying notes 86–90.

⁹² See Burrows, Law of Restitution, 47.

⁹³ Cobbe v Yeoman's Row Management [2008] UKHL 55; [2008] 1 W.L.R. 1752.

⁹⁴ Law Reform (Frustrated Contracts) Act 1943, s. 1(3).

⁹⁵ BP Exploration Co. (Libya) Ltd. v Hunt (No. 2) [1979] 1 W.L.R. 783, 801, per Goff J.

⁹⁶ Virgo, The Principles, 365.

⁹⁷ See e.g. Burrows, Law of Restitution, 67.

⁹⁸ Stevens, R., “Three Enrichment Issues” in Burrows, A. and Rodger, A. (eds.), Mapping the Law: Essays in Memory of Peter Birks (Oxford 2006), 54 Google Scholar.

⁹⁹ See Rhoode v De Kock [2012] ZASCA 179; 2013 (3) S.A. 123, at [15].

¹⁰⁰ Nortje N.O. 1966 3 S.A. 96 (A), 108.

¹⁰¹ ABSA Bank Ltd. t/a Bankfin v Stander t/a CAW Paneelkloppers 1998 1 S.A. 939 (C), 957.

¹⁰² Fletcher & Fletcher v Bulawayo Waterworks Co. Ltd. 1915 A.D. 636, 641.

¹⁰³ Benedetti [2013] UKSC 50; [2014] A.C. 938, at [119].

¹⁰⁴ Ibid., at paras. [16]–[17], per Lord Clarke; Benedetti v Sawiris [2010] EWCA Civ 1427, at [140], per Etherton L.J.

¹⁰⁵ Sempra Metals [2007] UKHL 34; [2008] 1 A.C. 561, per Lord Nicholls; Burrows, Law of Restitution, 44; Virgo, The Principles, 67–68. Cf. the somewhat confused implication that subjective devaluation is available only to an “involuntary recipient” in Littlewoods Retail Ltd. v Revenue and Customs Commissioners [2015] EWCA Civ 515; [2015] 3 W.L.R. 1748, at [195].

¹⁰⁶ Benedetti [2013] UKSC 50; [2014] A.C. 938, at [21].

¹⁰⁷ Ibid., at paras. [122]–[123]; Harrison v Madejski [2014] EWCA Civ 361; [2016] Ch. 373, at [57].

¹⁰⁸ Benedetti [2013] UKSC 50; [2014] A.C. 938, at [100]–[109], [119].

¹⁰⁹ Ibid., at para. [22].

¹¹⁰ Ibid., at para. [29] per Lord Clarke; paras. [120]–[121] per Lord Reed; para. [195] per Lord Neuberger; see also Goff, R. and Jones, G., The Law of Unjust Enrichment, 8th ed. (London, 2011)Google Scholar, [4–11]; Virgo, The Principles, 88–89.

¹¹¹ I am indebted to Professor Robert Stevens for this example and the variations on it below.

¹¹² See generally A. Burrows, Restatement of the English Law of Unjust Enrichment (2012), 158.

¹¹³ Benedetti [2013] UKSC 50; [2014] A.C. 938, at [31].

¹¹⁴ Brenner [1993] 2 V.R. 221, 258.

¹¹⁵ Benedetti [2013] UKSC 50; [2014] A.C. 938, at [120].

¹¹⁶ McInnes, M., “Enrichments and Reasons for Restitution: Protecting Freedom of Choice” (2003) 48 McGill L.J. 419, 449–50Google Scholar.

¹¹⁷ Benedetti [2013] UKSC 50; [2014] A.C. 938, at [120]–[121].

¹¹⁸ Burrows, Law of Restitution, 60–61, cited with approval in Benedetti [2013] UKSC 50; [2014] A.C. 938, at [121].

¹¹⁹ See above, text accompanying notes 68–71.

¹²⁰ Benedetti [2013] UKSC 50; [2014] A.C. 938, at [29]; see also Burrows, Restatement, 158; but cf. Burrows, Law of Restitution, 60.

¹²¹ See above, text accompanying notes 51–53.

¹²² Benedetti [2013] UKSC 50; [2014] A.C. 938, at [100]–[101].

¹²³ The problem is not dealt with at paras. [120]–[121], where Lord Reed comments only on the tangential debate of whether subjective overvaluation plays a role in assessing services that objectively add no value to land.

¹²⁴ McInnes, “Enrichments and Reasons”, 449.

¹²⁵ Degeling, S. and Roque, M. San, “Unjust Enrichment: A Feminist Critique of Enrichment” (2014) 36 Syd.L.R.69, 96 Google Scholar.

¹²⁶ E.g. Pettkus v Becker [1980] 2 S.C.R. 834; Deglman v Guaranty Trust Co. [1954] S.C.R. 725.

¹²⁷ Benedetti [2013] UKSC 50; [2014] A.C. 938, at [197]–[198].

¹²⁸ See above, text accompanying notes 86–90.

¹²⁹ Benedetti [2013] UKSC 50; [2014] A.C. 938, at [34].

¹³⁰ Although a similar proposition was rejected by Stephen Morris Q.C. in Diamandis v Wills [2015] EWHC 312 (Ch), at [94]–[95], his comments were made in obiter in the context of a strike-out application and without the benefit of full argument.

¹³¹ This is related to, but conceptually distinct from, the prohibition on recovery for “risk-takers”, or volunteers, who confer a benefit directly on another in the hope of reward, as in the case of the officious cobbler hypothetical in Taylor v Laird (1856) 25 L.J. Ex. 329, 332, per Pollock C.B.

¹³² Birks, P., Unjust Enrichment, 2nd ed. (Oxford 2005), 158–60CrossRefGoogle Scholar.

¹³³ Ruabon Steamship Company Ltd. v The London Assurance [1900] A.C. 6, 12; Burrows, Restatement, 54.

¹³⁴ TFL Management Ltd. [2013] EWCA Civ 1415; [2014] 1 W.L.R. 2006.

¹³⁵ Ibid., at para. [86].

¹³⁶ Ibid., at para. [19].

¹³⁷ Ibid., at para. [37].

¹³⁸ Burrows, Restatement, 54 (Rule 8(4)). See also the materially similar formulation advanced by the Bank in TFL Management Ltd. [2013] EWCA Civ 1415; [2014] 1 W.L.R. 2006, at [22].

¹³⁹ Goff and Jones, Law of Unjust Enrichment, para. [4–52]; see also the position in Scots law: Jones v Muir 2015 G.W.D. 11–183, at [7]; Shilliday v Smith 1998 S.C. 725, 730 (no recovery for claimant acting “in their own interest but which incidentally benefits someone else”).

¹⁴⁰ Burns v McLellan's Creditors (1735) Mor. 13402, 6240.

¹⁴¹ For a detailed discussion, see McCamus, J., “The Self-Serving Intermeddler and the Law of Restitution” (1978) 16 Osgoode Hall L.J. 515 Google Scholar.

¹⁴² Greenwood [1973] Q.B. 195.

¹⁴³ See TFL Management Ltd. [2013] EWCA Civ 1415; [2014] 1 W.L.R. 2006, at [85].

¹⁴⁴ Shilliday 1998 S.C. 725, 743, emphasis added; see also below, text accompanying notes 188–189.

¹⁴⁵ Barton v Armstrong [1976] A.C. 104.

¹⁴⁶ For this example I am indebted to Professor Robert Stevens.

¹⁴⁷ Sellar, W. D. H., “ Shilliday v Smith: Unjust Enrichment through the Looking Glass?” (2001) 5 Edin.L.R. 80, 84Google Scholar.

¹⁴⁸ Oxford Dictionary of English (Oxford 2010), 884 (“incidental”).

¹⁴⁹ Van der Garde B.V. v Force India Formula One Team Ltd. [2010] EWHC 2373 (QB), at [257].

¹⁵⁰ Sempra Metals [2007] UKHL 34; [2008] 1 A.C. 561.

¹⁵¹ Burrows, Restatement, 55.

¹⁵² Ibid., at p. 54 (Rule 8(4)); TFL Management Ltd. [2013] EWCA Civ 1415; [2014] 1 W.L.R. 2006, at [22].

¹⁵³ Goff and Jones, Law of Unjust Enrichment, para. [4–52]; see also the position in Scots law: Jones 2015 G.W.D. 11–183, at [7]; Shilliday 1998 S.C. 725, 730.

¹⁵⁴ Jones 2015 G.W.D. 11–183.

¹⁵⁵ Ibid., at para. [7(1)].

¹⁵⁶ Ibid., at para. [6].

¹⁵⁷ McInnes, M., “The Reason to Reverse: Unjust Factors and Juristic Reasons” (2012) 92 B.U.L.Rev. 1049, 1064 Google Scholar.

¹⁵⁸ See Burrows, Law of Restitution, 66; Menelaou [2015] UKSC 66; [2016] A.C. 176 at [38] per Floyd L.J.

¹⁵⁹ See Friedmann, D., “Unjust Enrichment, Pursuance of Self-Interest, and the Limits of Free Riding” (2003) 36 Loy.L.A.L.Rev. 831, 845 Google Scholar; Wilmot-Smith, F., “Taxing Questions” (2015) 131 L.Q.R. 531, 534 Google Scholar.

¹⁶⁰ TFL Management Ltd. [2013] EWCA Civ 1415; [2014] 1 W.L.R. 2006.

¹⁶¹ Explora Group Plc v Hesco Bastion Ltd. [2005] EWCA Civ 646.

¹⁶² Cobbe [2008] UKHL 55; [2008] 1 W.L.R. 1752, at [41].

¹⁶³ See e.g. Macdonald v McCall (1887) 12 P.R. 9 (Ont); McCamus, “Self-Serving Intermeddler”, 559–75.

¹⁶⁴ Hume, D., Lectures 1786–1822, vol. III (Edinburgh 1952), 166, n. 8Google Scholar.

¹⁶⁵ See Shilliday 1998 S.C. 725, 731.

¹⁶⁶ Gloag and Henderson, Law of Scotland, 12th ed. (Edinburgh, 2007), 523–24.

¹⁶⁷ Whitty, N., “ Transco plc v Glasgow City Council: Developing Enrichment Law after Shilliday ” (2006) 10 Edin.L.Rev. 112, 118 Google Scholar.

¹⁶⁸ Sellar, “Shilliday v Smith”, 84.

¹⁶⁹ Edinburgh and District Tramways v Courtenay 1909 S.C. 99, 105, cited with approval in Corrie v Craig 2013 G.W.D. 1–55, at [31].

¹⁷⁰ Stewart v Steuart (1878) 6 R. 145, 149.

¹⁷¹ Exchange Telegraph Co. Ltd. v Giulianotti 1959 S.C. 19, 26.

¹⁷² Edinburgh & District Tramways Co. Ltd. 1909 S.C. 99.

¹⁷³ TFL Management Ltd. [2013] EWCA Civ 1415; [2014] 1 W.L.R. 2006, at [36].

¹⁷⁴ Ulmer v Farnsworth 15 A. 65 (1888).

¹⁷⁵ Ruabon Steamship Company Ltd. [1900] A.C. 6. Similarly, see Crouan v Stanier [1904] 1 K.B. 87, 94; The Acanthus [1902] P. 17.

¹⁷⁶ The enrichment was also not unjust, because the occupier parents had walked away from their rights voluntarily: Jones 2015 G.W.D. 11–183, at [6].

¹⁷⁷ Burrows, Restatement, 55.

¹⁷⁸ Cf. Sempra Metals [2007] UKHL 34; [2008] 1 A.C. 561; see also above, text accompanying notes 14, 85, 148.

¹⁷⁹ See generally Burrows, Law of Restitution, ch. 17.

¹⁸⁰ Cf. above, text accompanying note 149.

¹⁸¹ See generally Friedmann, “Unjust Enrichment”, 845–51.

¹⁸² Ulmer 15 A. 65 (Me. 1888); see also Berry & Gould v Berry 757 A.2d 108, 116 (Md. 2000).

¹⁸³ Orr v Graham (1831) 10 S. 135.

¹⁸⁴ Knaus v Dennler 525 N.E. 2d. 207, 208–210 (Ill. App. Ct. 1988).

¹⁸⁵ So as to exclude, to the extent it exists, the application of the doctrine of necessity: see Burrows, Law of Restitution, ch. 18.

¹⁸⁶ Edinburgh & District Tramways Co. Ltd. 1909 S.C. 99, 106.

¹⁸⁷ Ruabon Steamship Company Ltd. [1900] A.C. 6.

¹⁸⁸ Taylor (1856) 25 L.J. Ex. 329, 332, per Pollock C.B.; cf. the discussion of “free acceptance” as an unjust factor in Birks, An Introduction, p. 104.

¹⁸⁹ Becerra v Close Bros Corporate Finance Ltd. (unreported 25 June 1999).

¹⁹⁰ Chartered Brands Limited v Elmwood Design Limited 2006 G.W.D. 27–599, at [76]; ibid.

¹⁹¹ Becerra (unreported 25 June 1999).

¹⁹² See Regalian Properties Ltd. v London Docklands Development Corporation [1995] 1 W.L.R. 212.

¹⁹³ Cf. William Lacey (Hounslow) Ltd. v Davis [1957] 1 W.L.R. 932, 939.

¹⁹⁴ Roxborough [2001] HCA 68; (2001) 208 C.L.R. 516, at [101]–[102].

¹⁹⁵ Shilliday 1998 S.C. 725, 730, 734, 735.

¹⁹⁶ Fernie v Robertson (1871) 9 M. 437, 442.

¹⁹⁷ TFL Management Ltd. [2013] EWCA Civ 1415; [2014] 1 W.L.R. 2006, at [37].