¹ [1990] Q.B. 391 (Slade, Stocker and Bingham L.J.J.).

² The case has now been settled. Another case in which the elements of the tort of conspiracy could fall for review by the House of Lords is Lonrho P.l.c. v. Fayed [1989] 3 W.L.R. 631 (C. A.)Google Scholar. Leave to appeal to the House of Lords has been granted, and the appeal is expected to be heard in 1991.

³ [1982] A.C. 173.

⁴ It is worthy of note that the clearest authority which explains the significance of a plea of conspiracy to injure by unlawful means, Kearney v. Lloyd (1889) 26 LR Ir. 268Google Scholar, was decided prior to Quinn v. Leathern [1901] A.C. 495Google Scholar, and so failed to consider the new, tort of conspiracy to injure by lawful means established in the later case. After Quinn v. Leathern, Kearney v. Lloyd disappeared from view. But a dictum of Palles C.B. in the earlier case, at p. 280 of the report, captures the importance of a conspiracy plea in a case where unlawful means are to be used: “[conspiracy is available] as making the defendants jointly responsible for the acts done in pursuance of it” (his emphasis). Throughout this article, where I refer to secondary liability I mean liability imposed on a person who assists in or procures the commission of an actionable civil wrong by another, in a manner similar to the imposition of liability in criminal law upon a person who aids, abets, counsels or procures the commission of a crime.

⁵ See e.g. Crofter Handwoven Harris Tweed Co Ltd v. Veitch [1942] A.C. 435Google Scholar.

⁶ As, for example, to improve their commercial position in the market: Mogul Steamship Co. v. McGregor, Gow & Co. [1892] A.C. 25Google Scholar; or to promote the interests of trade union members through collective bargaining: the Crofter case [1942] A.C. 435.

⁷ See e.g. Huntley v. Thornton [1957] 1 W.L.R. 321Google Scholar (actions taken to assuage the offended dignity of trade union officials).

⁸ See Metall und Rohstoff [1990] Q.B. 391, 452Google Scholar, referring to Salmond & Heuston Law of Torts 18th ed. 1981, pp. 353–4Google Scholar: “A second form of actionable conspiracy exists when two or more combine to injure a third person by unlawful means— e.g. the commission of a crime or tort … In such a case it is irrelevant that the object of the conspirators in using those means may be legitimate”; also Winfield and Jolowicz on Tort, 11th ed. by Rogers, W. V. H., 1979, p. 496Google Scholar and Street on The Law of Torts 6th ed., 1976, p. 348Google Scholar.

⁹ [1990] Q.B. 391 at 453–454.

¹⁰ [1964] A.C. 1129 at 1204. The Court of Appeal in Metall und Rohstoff referred in addition to the following: Mogul Steamship [1892] A.C. 25, 41–42per Watson, LordGoogle Scholar; Quinn v. Leathern [1901] A.C. 495, 528per Brampton, LordGoogle Scholar; the Crofter case [1942] A.C. 435, 446, 447per Viscount, Simon L.C., 469 per Lord WrightGoogle Scholar; and to a number of other statements in these cases and in Sorrell v. Smith [1925] A.C. 700Google Scholar and in Rookes v. Barnard [1964] A.C. 1129Google Scholar: see [1990] Q.B. 391 at 453–454.

¹¹ [1901] A.C. 495.

¹² There are numerous other citations which support this view: see notes 9 and 10 above.

¹³ [1990] Q.B. 391 at 454.

¹⁴ “In Mogul, Sorrell v. Smith and Crofter the plaintiffs failed because they failed to show that the alleged conspirators had such a purpose; in each case the alleged conspirators also had lawful interests which they sought to protect by means not in themselves unlawful. In Quinn v. Leathern the plaintiff succeeded, but he there established a sole purpose of causing injury”, at [1990] Q.B. 391, 454.

¹⁵ This is often the case with obiter dicta, delivered without being part of the heart of the reasoning in a particular case, and, it may be, moving off at a tangent from such reasoning. That is one reason why such dicta are treated as authoritative but not binding pronouncements. If the language of a judicial decision in a particular case is not to be construed as if it was the language of a statute, that must be doubly true of the language of obiter dicta, delivered on the margins of the reasoning in a case, where the pressure for tight and precise formulation is correspondingly diminished. This is particularly so in the context of judicial observations about the law of conspiracy, and has been emphasised on a number of occasions: see e.g. Quinn v. Leathern [1901] A.C. 495, 506per Lord, Halsbury L.C.Google Scholar, Sorrell v. Smith [1925] A.C. 700, 717per Dunedin, Lord, 744 per Lord BuckmasterGoogle Scholar, Crofter [1942] A.C. 435, 442per Viscount, Simon L.C., 472 per Lord Wright, 492 per Lord PorterGoogle Scholar.

¹⁶ Mogul Steamship, Quinn v. Leathern, Sorrell v. Smith and Crofter were all cases of conspiracy to injure by lawful means.

¹⁷ See note 8 above.

¹⁸ One consequence of the decision in Metall und Rohstoff is that it is unclear what would be an illegitimate interest in the context of the tort of conspiracy. In the older cases, in which the concept of the pursuit of a “legitimate interest” was introduced as a defence to the tort of conspiracy to injure by lawful means, the concept of legitimacy was more straightforward, as the rest of the law defining what was lawful or unlawful provided one standard to be applied (although there remained scope for argument about what was “legitimate” where no breaches of law were contemplated: see Crofter [1942] A.C. 435Google Scholar). Now, however, conspirators may be pursuing a “legitimate interest” even when acting illegally in seeking to promote their own self-interest.

¹⁹ Acts which are criminal but not tortious may be relevant in establishing the tort of conspiracy to injure by unlawful means in this way: the underlying primary torts relied on by the plaintiff against the conspirators might include the tort of interference with business by unlawful means, where the unlawful means relied on are criminal acts. In such a case, the conspirator who commits the criminal acts in question with a view to injuring the plaintiff could be individually liable for the tort of interfering with the plaintiff's business by unlawful means, and his co-conspirators would then become liable in respect of that tort in accordance with the rules of civil secondary liability which are discussed later in this article. Whether primary individual liability would be made out on the basis of criminal (but not tortious) acts is, at the moment, unclear: see Carty, (1988) 104 L.Q.R. 250, 267–271Google Scholar; Lonrho v. Shell (No. 2) and Associated British Ports v. TGWU [1989] 1 W.L.R. 939Google Scholar. The questions of policy involved are by no means easy, and full discussion of this primary tort lies outside the scope of this article. Whatever the position, it is clear that liability for conspiracy to injure by unlawful means cannot be explained simply as an example of the tort of interference with business by unlawful means. For that tort to be made out, the unlawful means employed have to be unlawful acts of the defendant which cause loss to the plaintiff through their effect on third parties. But a conspirator may be made liable in respect of the unlawful acts of others. It is not sufficient to say that the agreement to injure the plaintiff is itself a criminal conspiracy, and that as such it constitutes the unlawful means necessary to treat the conspirator as liable for the primary tort of interference with the plaintiff's business by unlawful means. The agreement of itself has no effect on the plaintiff; it is only when it is acted upon and the plaintiff suffers loss that he may sue the conspirators. Thus the plaintiff needs to treat each of the conspirators as responsible for the unlawful acts of all the others; this may only be acieved in the form of secondary liability of some sort.

²⁰ See, e.g., Lonrho P.l.c. v. Fayed [1989] 3 W.L.R. 631 (C.A.)Google Scholar, following Metall und Rohstoff. In Derby & Co. v. Weldon (No. 5) [1989] 1 W.L.R. 1244Vinelott, J.Google Scholar. refused to strike out a claim based on conspiracy to use unlawful means on the authority of Metall und Rohstoff, partly on the ground that leave to appeal to the House of Lords had been granted in that case. Although Metall und Rohstoff has now been settled, striking out may still be inappropriate in view of the pending appeal to the House of Lords in Lonrho P.l.c. v. Fayed.

²¹ See the conflicting decisions in Metall und Rohstoff at first instance, per Gatehouse, J., [1990] Q.B. 391Google Scholar and Allied Arab Bank Ltd v. Hajjar (No. 2) [1988] Q.B. 944, per Hirst, J.Google Scholar

²² Even the Court of Appeal in Metall und Rohstoff expressed the view that it would not have been unhappy to reach the same conclusion as the judge (i.e. in favour of the plaintiff) on the conspiracy point: [1990] Q.B. 391 at 466.

²³ Certain other causes of action were potentially made out so that the plaintiff was granted leave to serve its writ, not including a claim for conspiracy, outside the jurisdiction against the defendants. The question of whether the tort of conspiracy is mere surplusage where other torts or civil wrongs are established is discussed below.

²⁴ [1990] Q.B. 391.

²⁵ [1982] A.C. 173, 188–189.

²⁶ ibid.

²⁷ [1990] Q.B. 391, 459–460.

²⁸ The significance of the distinction between situations (a) and (b) on the one hand and situations (c) and (d) on the other is further discussed below.

²⁹ A limitation on liability derived from the cases in relation to conspiracy to injure using lawful means: see e.g. Sorrell v. Smith and Crofter.

³⁰ Lord Diplock's criticism of this basis for the tort, that a single large commercial entity may be capable of causing more harm acting alone than a number of small entities acting together, is specifically addressed in modern legislative approaches to control of unfair competition: e.g. by the dual prohibition of cartels between a number of entities in Article 85 of the Treaty of Rome and the prohibition of abuse of a dominant position in a market by a single entity under Article 86. For further criticisms of this basis for the tort of conspiracy see Sorrell v. Smith [1925] A.C. 700, 740–1Google Scholarper Lord Sumner and Crofter [1942] A.C. 435, 443per Viscount, Simon L.C., 468 per Lord WrightGoogle Scholar.

³¹ As, for example, in the case of inducing breach of contract.

³² See e.g. South Wales Miners' Federation v. Glamorgan Coal Company Ltd [1903] 2 K.B. 545, 573–579 per Romer, and Stirling, L.JJ.Google Scholar; affd [1905] A.C. 239; Larkin v. Long [1915] A.C. 814Google Scholar; Associated British Ports v. TGWU [1989] 1 W.L.R. 939Google Scholar; and Melall und Rohstoff [1990] Q.B. 391, 454Google Scholar.

³³ Thus the law of contract is treated in one book and the law of tort in another, liability for direct inducement of breach of contract generally being treated in detail in the book on tort as one of the economic torts, rather than as a form of secondary liability for breach of contract.

³⁴ Not being limited to unlawfulness in the sense of wrongfulness in civil law, which would have clarified the basis of the tort, but being assumed to include wrongfulness in criminal law also: see note 8 above.

³⁵ The language is that of section 8 of the Accessories and Abettors Act 1861, but secondary liability for crimes preceded that statute and was originally a development of the common law: see e.g. Manley (1844) 1 Cox C.C. 104Google Scholar and Mazeau (1840) 9 C.&P. 676Google Scholar. These are instances of true secondary liability, and are to be contrasted with cases which turn on the “innocent agent” doctrine, whereby a person may be guilty of an offence where the actus reus (e.g. the administration of poison) is committed by an innocent agent, so that the guilty party is liable as a principal, and not as a secondary party: see (1634) Kelyng 53, Michael (1840) 9 C.&P. 356Google Scholar and Bull and Schmidt (1845) 1 Cox C.C. 281Google Scholar; and Archbold, Pleading Evidence and Practice in Criminal Cases, 2nd ed, 1825, pp. 398ffGoogle Scholar.

³⁶ Lumley v. Gye (1853) 2 E&B 216Google Scholar; DC. Thomson & Co. Ltd. v. Deakin [1952] Ch. 646, 697 per Jenkins, L. J.Google Scholar Such liability is distinct from liability for inducing breach of contract or interfering with the performance of a contract by unlawful means, which are forms of primary liability—they do not depend on there being any breach of contract and it is necessary that the defendant himself employ unlawful means. They are probably examples of a wider tort of interfering with another's business by unlawful means: see Carty, (1988) 104 L.Q.R. 250, 256Google Scholar and Associated British Ports v. TGWU [1989] 1 W.L.R. 939Google Scholar. Also see note 19 above.

³⁷ See in particular the judgment of Erie, J. in the leading case of Lumley v. Gye (1853) 2 E.&B. 216, 232Google Scholar.

³⁸ See Alleyne v. Darcy (1854) 4 Ir. Ch. Rep. 199; Eaves v. Hickson (1861) 30 Beav. 136Google Scholar; Midgley v. Midgley [1893] 3 Ch. 282Google Scholar. See also Metall und Rohstoff [1990] Q.B. 391, 481Google Scholar. The best discussion is in Harpum (1986) 102 L.Q.R.. at 141–144Google Scholar.

³⁹ Pane v. Lamont (1842) Car. & M. 93, 96per Tindal, C.J.Google Scholar; M'Laughlin v. Pryor (1842) 4 Man. & G. 48Google Scholar; Marsh v. Conquest (1864) 17 C.B. (N.S.) 418Google Scholar; Cargill v. Bower (1878) Ch. D. 502, 513–514per Fry, J.Google Scholar; Weir v. Bell (1878) 3 Ex. D. 238, 247–248per Cockburn, L.J.Google Scholar; Donovan v. Laing, Wharton and Down Construction Syndicate [1893] 1 Q.B. 629, 634per Bowen, L.J.Google Scholar; Pratt v. British Medical Association [1919] 1 K.B. 244, 254–255per McCardie, J.Google Scholar; The Koursk [1924] P. 140, 155per Scrutton, L.J.Google Scholar; Performing Rights Society Ltd v. Mitchell and Booker (Palais de Danse) Ltd. [1924] 1 K.B. 762, 765per McCardie, J.Google Scholar; Yuille v. B&B Fisheries (Leigh) Ltd. [1958] 2 Lloyd's Rep. 596, 617–619Google Scholar. As an example, persons who control the activities of a corporate body are liable in respect of any wrong of that body which they procured: Rainham Chemical Works Ltd v. Belveder Fish Guano Co. [1921] 2 A.C. 465, 475–476per Buckmaster, LordGoogle Scholar; Performing Rights Society Ltd v. Ciryl Theatrical Syndicate Ltd [1924] 1 K.B. 1, 14–15per Atkin, L.J.Google Scholar; C. Evans v. Spritebrand Ltd [1985] 1 W.L.R. 317Google Scholar. See also the authorities cited in Clerk & Lindsell on Torts 15th ed. paragraph 2–55 and Glanville Williams Joint Torts and Contributory Negligence pp. 9–16. Notwithstanding these authorities, this principle has received little prominence in the law of tort. Recent development in the law of tort has tended to b e preoccupied with the expansion of negligence. It would be rare indeed that one would find a case in which a person would knowingly have caused another to act negligently. But it is possible to imagine cases in which secondary liability for negligence might be appropriate (e.g. where the defendant has deliberately distracted a third party's attention while he was doing something, with the intention that the plaintiff should suffer loss as a result, and where the third party cannot exculpate himself by saving that he was distracted).

⁴⁰ Meade v. Haringey London Borough Council [1979] 1 W.L.R. 637, 651per Eveleigh, L.J.Google Scholar; Associated British Ports v. Transport & General Workers' Union [1989] 1 W.L.R. 939, 951H–952E per Neill, L.J.Google Scholar, 959B–960A per Butler-Sloss L.J., 963D–964C per Stuart-Smith, L.J. (the decision of the Court of Appeal was subsequently reversed in the House of Lords, without reference to this point [1989] 1 W.L.R. 939, 970)Google Scholar.

⁴¹ Associated British Ports v. TGWU [1989] 1 W.L.R. 939Google Scholar, (C.A.) (reversed on other grounds in the House of Lords: [1989] 1 W.L.R. 939, 970).

⁴² Prudential Assurance Co. Ltd. v. Lorenz (1971) 11 K.I.R. 78Google Scholar.

⁴³ Seaward v. Paterson [1897] 1 Ch. 545.

⁴⁴ Secondary liability in respect of civil contempt of court is not based on the Accessories and Abettors Act 1861; instead it arises at common law.

⁴⁵ (1853) 2 E.&.B. 216.

⁴⁶ (1853) 2 E.&.B. 216, 232.

⁴⁷ [1898] A.C. 1.

⁴⁸ [1901] A.C. 495.

⁴⁹ [1898] A. C. 1,90; see also at p. 172 where Lord Davey, using the language of criminal secondary liability, talks of a person who induces a breach of contract as an “accessory”.

⁵⁰ Watson, Lord referred to Erie J.'s judgment twice, at [1898] A.C. 1, 96 and 106Google Scholar.

⁵¹ [1898] A.C. 1, 106–107.

⁵² [1901] A.C. 495, 510.

⁵³ [1901] A.C. 495, 535.

⁵⁴ [1989] 1 W.L.R. 939, reversed on other grounds in the House of Lords: ibid. p. 970.

⁵⁵ [1989] 1 W.L.R. at 952A.

⁵⁶ Ibid., at 959B–C; and see p. 963D–H per Stuart-Smith L.J., referring to a general tort of interference with rights, and to inducing breach of contract as the “commonest example of the tort”.

⁵⁷ One point which has not as yet been clarified in the authorities is the question of whether the limited defence of justification available in relation to inducing breach of contract should also be available in every other case of procuring the commission of a civil wrong. The most recent application of the defence in an inducing breach of contract case was in Edwin Hill and Partners v. First National Finance Corpn. P.l.c. [1989] 1 W.L.R. 225Google Scholar. In principle, there ought to be scope for the operation of this limited defence in other cases, not restricted to cases of procuring breach of contract.

⁵⁸ See e.g. Barnes v. Addy (1874) LR 9 Ch. App. 244Google Scholar, Belmont Finance Corporation Limited v. Williams Furniture Limited [1979] Ch. 250; the Baden Delvaux decision [1983] B.C.L.C. 325Google Scholar, 404g–i; Harpum, (1986) 102 L.Q.R. 114 and 267Google Scholar. The cases appear to require there to be dishonesty on the part of the trustee before those assisting in the breach of trust become liable. Harpum treats the cases referred to in note 38 above (knowing inducement of breach of trust) as establishing that the quality of the breach of trust by the trustee (i.e. whether it is dishonest or not) is irrelevant to the imposition of liability on the knowing inducer, and on this basis regards that ground of liability as different from liability for knowing assistance in a breach of trust (where there appears to be the requirement that the trustee has himself also acted dishonestly). However, as he observes, at (1986) 102 L.Q.R. 114, 144, the point at which mere assistance becomes instigation of a breach of trust cannot be defined precisely. It is submitted that there is really no difference in principle between knowing inducement and knowing assistance in a breach of trust, and that the elements of liability should be the same for each. The requirement that the breach of trust should itself be dishonest has been questioned elsewhere: see Loughlan, (1989) 9 O.J.L.S. 260CrossRefGoogle Scholar. When the analogy of this form of liability with other types of secondary liability in the civil law is emphasised, the requirement that the breach of trust which is assisted in should itself be dishonest appears superfluous. What is important is that there should have been an actionable civil wrong (whether dishonest or not), and a sufficient nexus between the loss suffered by the plaintiff as a result of that wrong and the person who has encouraged or assisted in its commission. That nexus is established by the plaintiff showing that the person inducing or assisting in the commission of the wrong acted knowing that he was inducing or assisting in the commission of that wrong.

⁵⁹ Equitable and common law principles are both referred to as examples of a general principle in Associated British Ports v. TGWU [1989] 1 W.L.R. 939, 959c per Butler-Sloss, L.J.Google Scholar.

⁶⁰ See the cases referred to in note 39 above.

⁶¹ Seaward v. Patterson [1897] 1 Ch. 545.

⁶² The requisite element of causation in the case of both inducement of and assistance in the commission of a civil wrong is broadly similar. In the case of an inducer, the plaintiff has to show that his action induced the third party wrongdoer to commit a wrong which otherwise “would or might never have been committed” (see Allen v. Flood [1898] A.C. 1, 107per Watson, LordGoogle Scholar, and see the text at note SI above; the causative potency required of the inducer's acts is less than in the case of interference with business by unlawful means: J. T. Stratford & Son Ltd. v. Lindley [1965] A.C. 269, 333C–334A per Pearce, Lord)Google Scholar. In the case of an assister, the plaintiff must show that his acts of assistance had more than minimal importance in the commission of the wrong: Baden Delvaux [1983] B.C.L.C. 325, 406g-h, per Peter, Gibson J.Google Scholar. See also Glanville Williams, Joint Torts and Contributory Negligence, pp. 14–15. Cf. the position in criminal law: Smith & Hogan Criminal Law, 6th ed., pp. 134–135.

⁶³ Here it is important that the criminal principles developed in the common law before they were codified in the Accessories and Abettors Act 1861: see note 35 above.

⁶⁴ For example, acts causing injury to people or damage to property; thus, e.g., the tort of battery is matched by the criminal offence of assault.

⁶⁵ See note 32 above.

⁶⁶ [1990] Q.B. 391, 454.

⁶⁷ For example, where workers strike, the loss suffered by their employer is usually the result o f their concerted action and cannot be attributed to any individual: see e.g. National Coal Board v. Galley [1958] 1 W.L.R. 16Google Scholar. Again, in a commercial context, a plaintiff's loss may only arise from the concerted actions of a number of defendants acting as a cartel to drive him out of business by a concerted course of action involving torts committed by numbers of people, where a single person committing torts alone would not have that effect. Vinelott J. posed a similar example in Derby & Co. v. Weldon (No. 5) [1989] 1 W.L.R. 1244 at 1254Google Scholar.

⁶⁸ The importance of a plea of conspiracy in increasing the damages available to the plaintiff has been recognised in the authorities: see Sorrell v. Smith [1925] A.C. 700, 713per Viscount, CaveL.C., p. 740 per Lord SumnerGoogle Scholar; Pratt v. British Medical Association [1919] 1 K.B. 244, 254per McCardie, J.Google Scholar The point is made most clearly in Kearney v. Lloyd (1889) 26 L.R. Ir. 268, 280per Palles, C.B.Google Scholar: see note 4 above. See also Larkin v. Long [1915] A.C. 814, 825–826per Lord, AtkinsonGoogle Scholar. Correspondingly, whilst a procurer or assister will be held to be jointly responsible for the commission of the civil wrong with the person who in fact carried out the wrongful acts, the damages recoverable from the procurer or assister may not be limited to those recoverable from the wrongdoer: Lumley v. Gye (1853) 2 E.& B. 216, 230per Crompton, J., 234 per Erie JGoogle Scholar.

⁶⁹ See e.g. Crofter [1942] A.C. 435, 441: Viscount, Simon L.C.Google Scholar rejected an argument advanced on behalf of the defendant McKnzie that he had obeyed orders from a superior within the trade union and therefore could not be liable for the tort of conspiracy. The defendants were successful, but on different grounds.

⁷⁰ In Pratt v. British Medical Association [1919] 1 K.B. 244, in which McCardie, J.Google Scholar expressly recognised the potentially wide ambit of civil secondary liability (at pp. 254–255 of the report), he said, in relation to a group of conspirators: “The liability, however, of each is independent of the mere circumstance of combination. That circumstance is, I conceive, only relevant to the question of the agency of one to bind the other by his acts, and to the point that greater damage may result where the wrongdoers are several or many. Conspiracy is not the gist of the matter.” While conspiracy to injure by unlawful means may, in one sense, not be the gist of the tort (the gist is the damage suffered by the plaintiff), it may plainly play an important part in a pleading, for the reasons given in the text. For some time, it was unclear whether the element of combination in conspiracy to injure by lawful means was an element of that tort either: see Sorrell v. Smith [1925] A.C. 700, 713per Viscount, Cave L.C.Google Scholar Yet the importance of being able to plead conspiracy was recognised: ibid.

⁷¹ [1990] Q.B. 391 at 460.

⁷² In Lonrho v. Shell (No. 2), the House of Lords addressed such considerations in deciding whether the breach of the statute in that case should carry with it a civil remedy for Lonrho. Lonrho's argument that there should be a civil remedy was rejected.