* We are grateful for valuable comments from Antony Duff, Andrew von Hirsch, Michael Prichard, Paul Roberts, Craig Rotherham, and Christian Witting.

1 Lumley v. Gye (1853) 2 E. & B. 216, 118 E.R. 749, confirmed in Allen v. Flood [1898] A.C. 1.

2 Cf. Lumley v. Wagner (1852) 1 De G. M. & G. 604, 42 E.R. 687.

3 See, e.g., D. Howarth, Textbook on Tort (London 1995), 484 (“Lumley v. Gye was wrongly decided”); Dan D. Dobbs, “Tortious Interference with Contractual Relationships” (1980) 34 Ark. L. Rev. 335, 345 (lamenting “the complete absence of any principle that will explain to us what judgments to make and why it is that liability sometimes is and sometimes is not imposed”); Lyn L. Stevens, “Interference with Economic Relations—Some Aspects of the Turmoil in the Intentional Torts” (1974) 12 Osgoode Hall L.J. 595, 595 (“illogical and piecemeal”).

4 Economic Torts (Oxford 1997), 28.

5 (1853) 2 E. & B. 216, 118 E.R. 749. C, a prominent soprano, had agreed with P (an opera impresario) to sing exclusively at Her Majesty's Theatre. D, a rival impresario, was alleged, knowing of C's obligation to P, to have persuaded C to sing instead at the Royal Italian Opera. On the point of law that arose from P's allegation, the Queen's Bench held that on such facts D would have committed a tort against P. (As it happens, the alleged facts were not later established at trial.) A valuable discussion of the case in its historical context is s.M. Waddams, “Johanna Wagner and the Rival Opera Houses” (2001) 117 L.Q.R. 431. Although a number of the judgments in Lumley v. Gye described C as a “servant”, by the end of the nineteenth century it was become clear that the tort extended to protect other forms of contract, ones not for employment or personal services. see Bowen v. Hall (1881) 6 Q.B.D. 333; Temperton v. Russell [1893] 1 Q.B. 715; C. Carpenter, “Interference with Contract Relations” (1928) 41 Harv. L.R. 728.

6 For convenience, we use the term “persuasion” in the text to cover any mode of persuasive inducement.

7 In particular, the distinction between persuasion or inducement and advice. We shall say a little more about this distinction infra, at p. 160.

8 Or at least an inadequate choice, as when D hinders performance without making it entirely impossible: cf. Dimbleby & Sons Ltd. v. NUJ [1984] 1 W.L.R. 67 (C.A.), not discussed on this point by the House of Lords [1984] 1 W.L.R. 427.

9 This is why, as we argue below, D's intention to harm P is indispensable to the prevention tort. (Indeed, the immediate wrong may be committed by or against a fourth party, E. This raises the further problem of indirect prevention, discussed below, at pp. 161ff.)

10 Indeed, C's right of recovery may be even more extensive than P’s, since C may sometimes be able to recover foreseeable contractual losses by suing D for the original unlawful act (as when D, a habitual arsonist, burns down C's factory, foreseeably preventing C from fulfilling her supply contracts with P; something to which D had given no thought).

11 Boulting v. Association of Cinematograph, Television and Allied Technicians [1963] 2 Q.B. 606, 639-640 (Upjohn L.J.); Williams v. Hursey (1959) 103 C.L.R. 30, 77; Brekkes v. Cattel [1972] 1 Ch. 105, 114 (Pennycuick V.-C.). Cf. Camden Exhibition & Display Ltd. v. Lynott [1966] 1 Q.B. 555, 569 (Russell L.J.).

12 Cf. Boulting v. Association of Cinematograph, Television and Allied Technicians [1963] 2 Q.B. 606, 639-640: C “must resist [D’s] effort by strength of will”.

13 Allen v. Flood [1898] A.C. 1, 120-121 (Lord Herschell); cf. Stratford v. Lindley [1965] A.C. 269, 340 (Lord Donovan).

14 And, indeed, to the principle ex turpi causa non oritur actio.

15 See, e.g., De Francesco v. Burnum (1890) 43 Ch. D. 165, (1890) 45 Ch. D. 430; Joe Lee Ltd. v. Dalmeny [1927] 1 Ch. 300; Greig v. Insole [1978] 3 All E.R. 449.

16 McManus v. Bowes [1938] 1 K.B. 98, 127 (Slesser L.J.); Cutsforth v. Mansfield Inns [1986] 1 W.L.R. 588, 563, D.C. Thomson & Co. Ltd. v. Deakin [1952] Ch. 646, 702 (Morris L.J.); Denaby and Cadeby Main Collieries Ltd. v. Yorkshire Miners’ Association [1906] A.C. 384, 406; Associated British Ports v. TGWU [1989] 1 W.L.R. 939, 970 (Stuart-Smith L.J.); White v. Riley [1921] 1 Ch. 1, 15, 26, 32.

17 Midland Cold Storage Ltd. v. Steer [1972] Ch. 630, 644-645; McKernan v. Fraser (1931) 46 C.L.R. 343.

18 Weir, above note 4, at p. 36 n. 44.

19 [1969] 2 Ch. 106 (C.A.).

20 Above, text at note 18.

21 Ibid., at p. 138.

22 Ibid. (italics omitted).

23 The decision may be explicable on two grounds. First, the contract did not exempt C from the (primary) obligation to supply fuel to the hotel, but rather exempted C from liability in the event that his failure to perform was prevented by, inter alia, a labour dispute of the sort that occurred. Thus the contract contained “an exception from liability for non-performance rather than an exception from obligation to perform” (per Russell L.J., ibid., at p. 143) and C was, in law, in breach of contract albeit that P could not sue. Second, the means used by D to prevent C from performing were in any event unlawful, since they involved procuring C's drivers to break their contracts of employment.

24 Lord Denning accepted a requirement of unlawfulness only where the intervention was indirect: “Indirect interference will not do…. Indirect interference is only unlawful if unlawful means are used”. (Ibid., at p. 138; italics in original.) We criticise the distinction between direct and indirect inteference below, at pp. 161ff.

25 Thomson & Co. Ltd. v. Deakin [1952] Ch. 646, 680 (Evershed M.R.); Torquay Hotel Co. Ltd. v. Cousins [1969] 2 Ch. 106, 138 (Lord Denning M.R.).

26 Per Evershed M.R. in Thomson & Co. Ltd. v. Deakin [1952] Ch. 646, 680, “it seems to me that the intervener, assuming in all cases that he knows of the contract and acts with the aim and object of procuring its breach to the damage of B, one of the contracting parties, will be liable … if he intervenes by the commission of some act wrongful in itself so as to prevent A from in fact performing his contract…”. Note that this proposition is subject to qualification, in that the unlawful means used by D must be a wrong against P; it is not enough that D's act is merely unlawful for some incidental reason. See the discussion infra, at p. 146; Lonrho Ltd. v. Shell Petroleum Co. Ltd. (No. 2) [1982] A.C. 173.

27 [1983] 2 A.C. 570, 608-609 (quoting with approval Lord Denning's statement of the principle reproduced above, text at n. 22). Cf. Law Debenture Trust Corp. v. Ural Caspian Oil Corp. Ltd. [1995] Ch. 152, 167 (Beldam L.J.): “it is an actionable tort knowingly to interfere with another's right to performance of a contractual obligation by preventing or hindering the other party from performing his obligations under the contract”. But compare, from the same judgment, infra n. 29. See too D.C. Thomson & Co. Ltd. v. Deakin [1952] Ch. 646, 694-695 (Jenkins L.J.), allowing that there would be liability where D “does an act which, if done by one of the parties to it, would have been a breach”. Prima facie, this asserts no requirement for unlawfulness independent of the contract, but Jenkins L.J. continues: “[o]f this type of interference the case of G.W.K. Ld. v. Dunlop Rubber Co. Ld. 42 T.L.R. 376 affords a striking example”. That case, the facts of which form the basis of our paradigm Case 2, clearly involved intervention by an unlawful act.

28 Although Lord Diplock cited the judgment of Jenkins L.J. in D.C. Thomson & Co. Ltd. v. Deakin [1952] Ch. 646, Jenkins L.J. never contemplated interference falling short of a breach. Moreover, his Lordship relied on the fact that Parliament had, in the then Trade Union and Labour Relations Act 1974, s. 13(1), granted certain immunities from liability for the tort of interference with contract, as evidence that the tort did exist at common law. But that provision was broadly drafted in case of future developments in tort law, not on the basis that such a tort then existed (cf. Rookes v. Barnard [1964] A.C. 1129, 1177 per Lord Reid).

29 E.g., Law Debenture Trust Corp. v. Ural Caspian Oil Corp. Ltd. [1993] 1 W.L.R. 138, 151 (Hoffmann L.J.), where Lord Denning's proposal is regarded as “debatable”. The decision was reversed on other grounds ([1995] Ch. 152, C.A.), where Beldam L.J. remarked (at 170) that “I am not persuaded that an act, otherwise lawful but which to the knowledge of the person doing it might prevent a third party from seeking equitable relief against breach of a primary obligation under a contract, is in itself capable of giving rise to a cause of action in tort”. Cf. also Middlebrook Mushrooms Ltd. v. TGWU [1993] I.C.R. 612, 620 (Neill L.J.).

30 See, e.g., K.W. Wedderburn, The Worker and the Law (3rd edn., Harmondsworth 1986), 611617; Howarth, above note 3, at p. 484; Weir, above note 4, at pp. 36-39; B. Markesinis and S. Deakin, Tort Law (4th edn., Oxford 1999), 476 477; W.V.H. Rogers (ed.), Winfield and Jolowicz on Tort (15th edn., 1998) 631-632.

31 [1952] Ch. 646, 693.

32 For example, News Group Newspapers v. SOGAT (No. 2) [1987] I.C.R. 181; Falconer v. ASLEF [1986] I.R.L.R. 331; Dimbleby & Sons Ltd. v. NUJ [1984] 1 W.L.R. 427 (H.L.).

33 [1898] A.C. 1, 121 (Lord Herschell). Cf. The Nadezhda Krupskaya [1997] 2 Lloyd's L.R. 35, 40 (Rix J.); also F.B. Sayre, “Inducing Breach of Contract” (1923) 36 Harv. L.R. 663, 696ff.

34 A distinction to which we return, below, at p. 161.

35 Merkur Island, News Group Newspapers v. SOGAT [1987] I.C.R. 181; Falconer v. ASLEF [1986] I.R.L.R. 331 (but see n. 97 infra).

36 E.g., D.C. Thomson & Co. Ltd. v. Deakin [1952] Ch. 646, 697 (Jenkins L.J.); Torquay Hotel Co. Ltd. v. Cousins [1969] 2 Ch. 106, 138 (Lord Denning M.R.). By “acts with the intent to harm P”, we mean that D must be acting deliberately in order to harm P (either for its own sake or in order to achieve some further purpose of D’s); the injury to P, even if foreseen, must be more than a mere side-effect of D's actions—it must be something that D has sought to bring about. See further infra, n. 89 and text thereat.

37 See, e.g., Emerald Construction v. Lowthian [1966] 1 W.L.R. 691, 700-701 (Lord Denning M.R.); but see infra, n. 92.

38 Below, at pp. 154ff.

39 Above note 4, at p. 2.

40 Cf. J.S. Mill's stricture for state action in On Liberty (1859) ch. 1: “the only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others”.

41 This claim holds most straightforwardly for those torts, including inducing breach of contract, where an injunction is available against D's activity. In other torts, it may be that P is wronged, and D is responsible for that wrong, but D's activity is not ex ante wrongful. The explanation of these torts is more complex: liability may, for example, mandate that D assumes the risk his conduct creates (cf. Rylands v. Fletcher (1868) L.R. 3 H.L. 330). We cannot explore these varieties of torts here.

42 Related examples are discussed by J. Gardner and S.C. Shute, “The Wrongness of Rape” in J. Horder (ed.), Oxford Essays in Jurisprudence (4th series, Oxford 2000), 193, 201 and A.P. Simester and A. von Hirsch, “Rethinking the Offense Principle” (2002) 8 Legal Theory 269, 282.

43 At least, no right maintainable against P. T may still have possessory rights against someone else.

44 A useful survey can be found in Smith, Stephen A., “Towards a Theory of Contract” in Horder, J. (ed.), Oxford Essays in Jurisprudence (Fourth Series, Oxford 2000), 107Google Scholar.

45 J. Raz, “Promises in Morality and Law” (1982) 95 Harv. L.R. 916, 937. The objection is explored more fully by Smith, supra n. 44, at pp. 109ff.

46 Cf. such well-known cases as Felthouse v. Bindley (1862) 11 C.B. (N.S.) 859, 142 E.R. 1037.

47 See, e.g., the work of Patrick Atiyah, The Rise and Fall of Freedom of Contract (Oxford 1979); Promises, Morals and Law (Oxford 1981); “Contract, Promises and the Law of Obligations” in his Essays on Contract (Oxford 1986) 10.

48 For an argument along these lines, see Smith, above note 44. In Smith's account, promises are constitutive of a special relationship between promisor and promisee. Hence his account can be aligned with the one here, in that the special relationship, which is intrinsically valuable, can be regarded as a part of the promisor's stock of goods. Even so, given that these are voluntarily created goods, it is not obvious how Smith's move is enough by itself to satisfy the requirement for harm (as he thinks it does), without the further arguments made here.

49 It remains, of course, a prima facie reason against having such a tort, since it involves a circumvention of those strangers’ freedoms, a circumvention to which they have not assented. The harm at stake in inducing breach of contract must therefore be sufficient to outweigh the harm inflicted by restricting those freedoms.

50 See also J. Danforth, “Tortious Interference with Contract: A Reassertion of Society's Interest in Commercial Stability and Contractual Integrity” (1981) 81 Col. L.R. 1491, 1511ff. This is not to deny that non-fulfilment of a contractual promise may harm P, or that inducing breach of contract should protect against this harm; but the harm is parasitic. It provides a justification for intervention only once it is accepted that the institution of contract should be defended by the state. Once the case for a regime of contractual rights is accepted, further more specific harms may be crystallised by the rights themselves. The reservation here is that those more specific harms do not justify state intervention unless the regime by which they are created is itself justified.

51 See Coleman, J., Risks and Wrongs (Cambridge 1992), 350-354Google Scholar.

52 While this assumption seems to us to be reasonable, in principle it raises an empirical question that we cannot investigate here.

53 This practice is undermined even in the case of efficient breach; in our view, inducing breach of contract cuts across the distinction between efficient and inefficient breach. Thus the problem of efficient breach is no more a challenge to inducing breach of contract than it is to contract law itself—the former challenge is parasitic on the latter. Indeed, efficient breaches do not imply third parties at all, let alone third parties who initiate breaches. In any event, as we argue below, damages for persuasion to breach are measured by contractual damages; hence, the operation of any efficient breach doctrine would, as it should, feed indirectly to the tort by means of the contract.

54 Weir, “Chaos or Cosmos? Rookes, Stratford and the Economic Torts” [1964] C.L.J. 225, 226: it is “tortious intentionally to damage another by means of an act which the actor was not at liberty to commit”. Cf. Weir, above note 4, at p. 28.

55 “It is, however, not every ‘unlawful’ act or means which allows for an action in tort, even if damage is intended and caused”. Clerk and Lindsell on Torts (18th edn., 2000) § 24-91. For example, it appears that contempt of court does not count as unlawful means: Chapman v. Honig [1963] 2 Q.B. 502, approved in Harrow LBC v. Johnston [1997] 1 W.L.R. 459, 471 (Lord Hoffman); contrast Acrow (Automation) Ltd. v. Rex Chainbelt Inc. [1971] 3 All E.R. 1175. See H. Carty, “Intentional Violation of Economic Interests: The Limits of Common Law Liability” (1988) 104 L.Q.R. 250, 265ff.

56 Cf. Lonrho Ltd. v. Shell Petroleum Co. Ltd. (No. 2) [1982] A.C. 173.

57 [1898] A.C. 1.

58 Notwithstanding that it is a tort intentionally to inflict physical harm to the plaintiff, cf. Wilkinson v. Downton [1897] 2 Q.B. 57, 58-59. The division extends to negligence: “The infliction of physical injury to the person or property of another universally requires to be justified. The causing of economic loss does not”. Murphy v. Brentwood DC [1991] 1 A.C. 398, 487 (Lord Oliver).

59 As Weir argues, above note 4, at pp. 21ff.

60 See above, text at note 15.

61 Above, text at and following note 24.

62 Above note 4, at p. 35.

63 Neither, it seems, is this true of tort law more generally. See, e.g., Rookes v. Barnard [1964] A.C. 1129, 1209-1210 (Lord Devlin), Associated British Ports v. TGWU [1989] 1 W.L.R. 939 (C.A.; reversed on other grounds, ibid., H.L.), and Barretts and Baird (Wholesale) Ltd. v. IPCS [1987] I.R.L.R. 3, 9, where it is suggested that what constitutes an unlawful means may differ across different economic torts.

64 As Howarth puts it (above note 3, at p. 484), “there is no reason to give the plaintiff remedies beyond its contractual remedies …”.

65 “Inducing Breach of Contract” in J. Horder (ed.), Oxford Essays in Jurisprudence (Fourth Series, Oxford 2000), 131, 137.

66 An account that is not without precedent: see, e.g., F. Pollock, The Law of Torts (London 1887) 451; W. Anson, Principles of the English Law of Contract (10th edn., Oxford 1903) 242. See also R. Epstein, “Inducement of Breach of Contract as a Problem of Ostensible Ownership” (1987) 16 J. Leg. Stud. 1.

67 Above note 65, at pp. 146-148.

68 A point seen by Bagshaw: ibid., at pp. 137-138. Indeed, a similar objection might be made to the claim that P has a right to C's existing capacity to perform. Prima facie, such a right could generate a positive obligation of maintenance in strangers, e.g., to repair diminutions in C's capacity to perform.

69 “Intention in Tort Law” in D.G. Owen (ed.), Philosophical Foundations of Tort Law (Oxford 1995) 229, 239.

70 It is no accident that one of the film versions of Choderlos de Laclos's book, Les Liaisons Dangereuses, is entitled Cruel Intentions.

71 Cf. G. Lamond, “Coercion, Threats, and the Puzzle of Blackmail” in A.P. Simester and A.T.H. Smith (eds.), Harm and Culpability (Oxford 1996) 215. Lamond points out that a key difference between a blackmailing threat and an offer or a warning lies in the intentions of the person who delivers it.

72 For example, the distinction between vandalism and negligent property damage is not simply that the former is more culpable. Vandalism expresses a contempt for society and for the victim that negligently causing damage does not.

73 Thus advice that warns a person of the consequences is not persuasion: Cutsforth v. Mansfield Inns Ltd. [1986] 1 W.L.R. 558, 563 (Sir Neil Lawson). Neither is it a threat or intimidation: White v. Riley [1921] 1 Ch. 1, 13 (Lord Sterndale M.R.).

74 Finnis, supra n. 69. Finnis's depiction (at p. 241) of “the Allen v. Flood rule that motive or intention is irrelevant” is something of a misdescription. Intention is relevant, and not just in the case of conspiracies. Allen v. Flood only decides that it is insufficient.

75 J. Raz, “Promises and Obligations”, in P.M.S. Hacker and J. Raz (eds.), Law, Morality and Society (Oxford 1977) 210, 227-228.

76 Cf. Raz, “Promises in Morality and Law” (1982) 95 Harv. L.R. 916, 928: “The moral presuppositions of this conception of promising are the desirability of special bonds between people and the desirability of special relations that are voluntarily shaped and developed by the choice of participants”.

77 It does not follow, of course, that N should be able to sue U for breach of contract. He is wronged, but he suffers no legally-recognised harm.

78 Above note. 4, at p. 34 (italics in original).

79 Ibid., at p. 35.

80 Cf. P. Sales, “The Tort of Conspiracy and Civil Secondary Liability” [1990] C.L.J. 491, esp. 502ff; D.J. Ibbetson, A Historical Introduction to the Law of Obligations (Oxford 1999), 180 (noting that forms of civil secondary liability appear to have been founded upon analogies to the criminal law).

81 Above, text at note 19.

82 Above, text at note 15.

83 Lubenham Fidelities and Investments Co. Ltd. v. S Pembrokeshire DC (1986) 33 B.L.R. 39, 7376 (C.A.).

84 Merkur Island Shipping Corp. v. Laughton [1983] 2 A.C. 570, 608 (Lord Diplock); Middlebrook Mushrooms Ltd. v. TGWU [1993] I.C.R. 612, 621 (Neill L.J.).

85 Sometimes, knowledge of the contract will be imputed, especially in interlocutory hearings. But this appears to be an evidential rather than a substantive step, not being one that introduces liability for inadvertent acts of inducement: thus “a third party may be deemed to know of the almost certain existence of a contract and indeed of some of its likely terms” (Middlebrook Mushrooms Ltd. v. TGWU [1993] I.C.R. 612, 621 per Neill L.J.), this is really a matter of inference (cf. Stratford v. Lindley [1965] A.C. 269, 324: “reasonable to infer” per Lord Reid) from circumstances where anyone in D's position would have known of the existence of the relevant contracts; typically, where D is an experienced trade union official who is familiar with the workings of his industry (cf. Merkur Island Shipping Corp. v. Laughton [1983] 2 A.C. 570, 608, per Lord Diplock).

86 See, e.g., D.C. Thomson & Co. Ltd. v. Deakin [1952] 1 Ch. 646, 695 (Jenkins L.J.): “with knowledge of the contract and the intention of bringing about its breach”; Rookes v. Barnard [1964] A.C. 1129, 1212 (Lord Devlin).

87 Tort Law (4th edn.), 471-472.

88 Suppose that D fires his rifle, aiming to hit his enemy, P, in the distance. D can intend to kill P notwithstanding that, at that range, his likelihood of succeeding is low.

89 Another way of putting this division is that the purposes, or ends, for which D acts are the reasons why one acts. They motivate and explain D's action. Intention embraces both these and the intermediate steps (the means) that D undertakes in order to achieve those ends. Sideeffects are those outcomes that, whether or not foreseen by D, did not motivate him to act as he did. See Finnis, supra n. 69, at pp. 229ff; Finnis, “Intention and side-effects” in R.G. Frey and C.W. Morris (eds.), Liability and Responsibility (Cambridge 1991) 32; A.P. Simester and Winnie Chan, “Intention Thus Far” [1997] Crim. L.R. 704.

90 (185 3) 2 E. & B. 216, 118 E.R. 749.

91 [1966] 1 W.L.R. 691, 701. Cf. J.G. Fleming, The Law of Torts (9th edn., Sydney 1998), 762: in the context of inducing a breach of contract, “[i]ndifference is equated with intent”.

92 Above note 65, at p. 142. Wedderburn also suggests that recklessness is sufficient: A.M. Dugdale (gen. ed.), Clerk and Lindsell on Torts (18th edn., London 2000), § 24-20. But the case that both Bagshaw (at 141 n. 31) and Wedderburn (at n. 14) cite in support of that conclusion does not, in fact, do so. Emerald Construction Co. Ltd. v. Lowthian [1966] 1 W.L.R. 691 is a case where D sought (that is, intended) termination, by breach if necessary. It is thus a case of conditional intention to procure a breach, not one of recklessness. The judgment of Diplock L.J. makes this clear (at 704): “ignorance of the precise terms of the contract is not enough to show absence of intent to procure its breach. The element of intent needed to constitute the tort of unlawful procurement of a breach of contract is, in my view, sufficiently established if it be proved that the defendants intended the party procured to bring the contract to an end by breach of it if there were no way of bringing it to an end lawfully. A defendant who acts with such intent runs the risk that if the contract is broken as a result of the party acting in the manner in which he is procured to act by the defendant, the defendant will be liable in damages to the other party to the contract”. Compare Rickless v. United Artists [1986] F.S.R. 502 (in particular, the final paragraph from the unreported portion of the judgment by Hobhouse J.).

93 Millar v. Bassey [1994] E.M.L.R. 44, 64 (Peter Gibson L.J.). Compare K.W. Wedderburn, “Inducing Breach of Contract and Unlawful Interference with Trade” (1968) 31 M.L.R. 440, 445: “the flood of liability would engulf not only trade union officials but also the most innocent, competitive, profit-seeking trader”.

94 E.g., Weir, above note 4, at p. 13.

95 As Beldam L.J. pointed out in Millar v. Bassey [1994] E.M.L.R. 44, 51, “[i]t was not alleged … in Lumley v. Gye that the defendant Gye had any intention to cause harm to the plaintiff beyond an intention that Miss Wagner should break her contract with him”. See also Edwin Hill & Partners v. First National Finance Corp. [1989] 1 W.L.R. 225, 234 (Stuart-Smith L.J.), citing Smithies v. National Association of Operative Plasterers [1909] 1 K.B. 310, 316; South Wales Miners’ Federation v. Glamorgan Coal Co. [1905] A.C. 239, 244 (Earl of Halsbury L.C.), 246 (Lord Macnaghten). Of course, whether or not intended, actual loss will be required for P to be awarded damages.

96 Cf. Quinn v. Leathem [1901] A.C. 495, 510 (Lord Macnaghten).

97 Both Falconer v. ASLEF [1986] I.R.L.R. 331 and Millar v. Bassey [1994] E.M.L.R. 44 should be doubted for this reason.

98 For an example of the sufficient case, where non-performance itself is intended, suppose that C agrees to sell an old clock to P. D then persuades C to keep the clock because it is a family heirloom. D's intervention is not aimed at harming P, but it is a straightforward case of inducing breach of contract because D intends to induce P not to do what she promised.

99 Above note 86.

100 R.A. Buckley and R. Heuston, Salmond and Heuston on the Law of Torts (21st edn., London 1996), 352; H. Carty, An Analysis of the Economic Torts (Oxford 2001), 47. Cf. D.C. Thomson & Co. Ltd. v. Deakin [1952] Ch. 646, 686 (Evershed M.R.); Middlebrook Mushrooms Ltd. v. TGWU [1993] I.C.R. 612, 626 (Hoffmann L.J.).

101 Cf. H.L.A. Hart and T Honore, Causation in the Law (2nd edn., Oxford 1985), 54.

102 Cf. Square Grip Reinforcement Co. Ltd. v. Macdonald [1968] S.L.T. 65, 73 (col. 2).

103 As Winn L.J. thought in Torquay Hotel v. Cousins [1969] 2 Ch. 106, 147. So, too, Simonds J. in Camden Nominees Ltd. v. Forcey [1940] Ch. 352, 366: “[a]dvice which is intended to have persuasive effects is not distinguishable from inducement”. Analogously, even a silent picket may, because of the intention of the picketers, be persuasion: Union Traffic Ltd. v. TGWU [1989] I.R.L.R. 127, C.A.

104 Cf. D.C. Thomson & Co. Ltd. v. Deakin [1952] Ch. 646, 686 (Evershed M.R.).

105 Cf. Board of Broadview School Unit No. 18 v. Saskatchewan Teachers Federation (1972) 32 D.L.R. (3d) 33; Long v. Smithson (1918) 88 L.J.K.B. 223. See also CBS Songs v. Amstrad Consumer Electronics plc [1988] A.C. 1013, 1058 (Lord Templeman); approved in Credit Lyonnais Bank Nederland v. Export Credits Guarantee Dept [2000] 1 A.C. 486, 499 (Lord Woolf M.R.).

106 D.C. Thomson & Co. Ltd. v. Deakin [1952] Ch. 646, 681-682 (Evershed M.R.), 694-697 (Jenkins L.J.); Torquay Hotel Ltd. v. Cousins [1969] 2 Ch. 106, 138.

107 See D.C. Thomson & Co. Ltd. v. Deakin [1952] Ch. 646, 695-696, 702 (Jenkins L.J.); also GWK Ltd. v. Dunlop Rubber Co. (1926) 42 T.L.R. 376.

108 Even by Lord Denning: Torquay Hotel v. Cousins [1969] 2 Ch. 106, 138: “[i]ndirect interference is only unlawful if unlawful means are used” (italics omitted); D.C. Thomson & Co. Ltd. v. Deakin [1952] Ch. 646, 679-680 (Evershed M.R.), 696-698 (Jenkins L.J.).

109 See, e.g., D.C. Thomson & Co. Ltd. v. Deakin [1952] Ch. 646, 694, 702 (Jenkins L.J.); Torquay Hotel v. Cousins [1969] 2 Ch. 106, 138 (Lord Denning).

110 N.J. McBride and R Bagshaw, Tort Law (London 2001), 333 (emphasis in original). The authors’ claim that D will have induced a breach of contract is subject to the usual provisos about D's mental element and possible justifications. See also J.D. Heydon, Economic Torts (2nd edn., London 1978), 29, 31.

111 [1898] A.C. 1; above notes 33, 57. See also D.C. Thomson & Co. Ltd. v. Deakin [1952] Ch. 646, 693 (Evershed M.R.), quoted above in the text at n. 31. Or suppose that C has contracted to sell an asset to P. C is deeply in debt to D, who forces C into bankruptcy in order to prevent transfer of the asset.

112 Heydon (above note 110) cites Esso Petroleum Co. Ltd. v. Kingswood Motors (Addlestone) Ltd. [1974] 1 Q.B. 142 as authority that direct prevention can be a tort even when the means are lawful. But Esso v. Kingswood does not support his analysis, since in that case D (also a company) was the owner of C and the case is thus not accurately depicted as one of “prevention” by a third party. Moreover, the means used were in any event identified by Bridge J. (at 155-156) as unlawful, since they constituted a civil conspiracy to induce a breach of contract.

113 Finnis, above note 69.

114 For an interesting study of the American experience and the issues it raises, see C. Witting, “Of Principle and Prima Facie Tort” (1999) 25 Monash U.L.R. 295.

115 See the text above at pp. 157-8.

116 As Weir argues: A Casebook on Tort (9th edn., London 2000), 606.

117 Bagshaw, supra n. 65, at p. 148; “the most obvious way of drawing [the direct/indirect distinction] is to ask whether the interference occurred through the acts or omissions or some human agent interposed between the defendant and the contract”. For alternative accounts, offered without normative underpinnings, see Greig v. Insole [1978] 1 W.L.R. 302, 334 (Slade J.) and Middlebrook Mushrooms Ltd. v. TGWU [1993] I.C.R. 612, 625 (Hoffmann L.J.).

118 Bagshaw, above note 65, at p. 148.

119 Contra Bagshaw, ibid.