Steampunk Liability: Conspiracy to Harm and the Diversity of Legal Traditions Within the Common Law of Torts.

AuthorBowley, Greg


The tort of conspiracy to harm, which assigns liability expressly on the basis of the defendants' malicious motive, continues its anomalous existence, having outlived repeated unsuccessful attempts by senior common law courts to explain and justify its operation. Part I of this paper offers an overview of conspiracy to harm jurisprudence from its modern birth in Mogul Steamship to Lonrho. Part II argues that, despite efforts to develop justifications for the tort's existence over the last century, conspiracy to harm has been expressly recognized for the last four decades as both unjustifiable and an immovable fixture of Anglo-Canadian tort law. This understanding had, until recently, discouraged extension of the tort's anomalous principles of liability to other areas of English tort law. Part III considers a consequent shift in conspiracy to harm jurisprudence which has extended the tort's anomalous principles to unlawful means conspiracy, a superficially similar, but substantially distinct, tort. Part IV suggests the possibility that, rather than an inexplicable anomaly, conspiracy to harm might more accurately be thought of as a legal anachronism, a contemporary tort powered by a distinct body of normative principles left behind by the common law over a century ago. Recognizing that this category of tort liability is, unlike the balance of Anglo-Canadian tort law (and unlawful means conspiracy in particular), anchored in the distinct legal tradition of a different time highlights, and explains, the conceptual singularity of conspiracy to harm. On this understanding, rather than a source of conceptual entropy within the contemporary Anglo-Canadian law of torts, conspiracy to harm is recognized for what it is: a unique vestige of a distinct understanding of interpersonal liability, now all-but-extinct, but preserved within the broader structure of the common law of torts.


Ordinarily, subjective motive or purpose is understood as playing no role in the assignment of private liability at common law. As one commentator put it, "the law focuses exclusively on what the defendant was doing, either using or touching something belonging to another, or damaging something belonging to another in the course of doing something else." (1) The tort of conspiracy to harm, together with a small number of other tort doctrines, (2) stands out as exceptional in this context. This marginal component of modern Anglo-Canadian tort law assigns liability to concerted conduct that is intended to harm another on the basis of the wrongful motive of the conspirators and that succeeds in doing so. It is, perhaps, the tort's enduring anomalous status that has prompted the House of Lords to make several distinct efforts to explain its existence since the late 19th century. Since 1981, however, it seems to have stopped trying. (3) The acceptance of conspiracy to harm as anomalous and inexplicable has produced two distinct but equally problematic responses. Both responses result from a failure to recognize the distinction between conspiracy to harm and the superficially similar, but theoretically distinct, tort of unlawful means conspiracy. Unlawful means conspiracy assigns liability to all conspirators who have agreed to undertake a course of action harmful to the defendant which is advanced by unlawful means, regardless of their actual purpose in doing so and regardless of how many (or few) of the conspirators actually employ the agreed-upon unlawful means. (4)

The Supreme Court of Canada, in Canada Cement LaFarge Ltd v B.C. Lightweight Aggregate Ltd, (5) recognized conspiracy to harm as a "commercial anachronism" (6) of questionable utility, but nonetheless extended its perplexing reliance on wrongful intention to circumstances previously captured by unlawful means conspiracy. Contrast this with England, where Lord Neuberger suggested in Revenue and Customs Commissioners v Total Network SL1 that unlawful means conspiracy should be developed by analogy to the principles of conspiracy to harm. This paper argues that these decisions, both of which will hinder the future principled development of unlawful means conspiracy through inappropriate linkage to conspiracy to harm, flow from a widespread failure to recognize conspiracy to harm for what it is-a doctrinal remnant of a distinct understanding of justifiable interpersonal conduct.

While conspiracy to harm is, at this point, an entrenched anomaly in Anglo-Canadian tort law, this paper argues that it should not be seen as having no intelligible normative content. Rather, conspiracy to harm is, I suggest, a contemporary manifestation of a long-abandoned general principle of liability for the intentional infliction of harm. (8) Judicial attempts to offer substantive explanations for the existence of this doctrine have, on the contrary, ignored legally significant motive as a possible explanation for the tort's existence and operation. On those occasions in which courts have tried to justify the tort's imposition of liability, the focus has been almost exclusively on the fact that, in conspiracy to harm, the wrongfulness of any particular conduct may turn exclusively on the fact that it was undertaken in concert rather than singly. This focus on the role of combination in the tort's assignment of liability has created a circumstance in which combination is considered to be the only salient structural aspect of conspiracy to harm, paving the way for the drawing of inappropriate linkages with conspiracy to use unlawful means in LaFarge and Total Network solely on the basis that both torts impose liability on the basis of concerted conduct.

The argument presented here is advanced as follows: Part I provides an overview of the tort of conspiracy to harm through the House of Lords' "famous trilogy," (9) Mogul Steamship Co Ltd v McGregor, Gow, & Co, (10) Allen v Flood, (11) and Quinn v Leathem. (12) These decisions have been characterized by the House of Lords as standing, collectively, for the propositions that 1) a combination of two or more persons to wilfully harm another is unlawful and, if it results in harm to that person, is actionable, and 2) if the real purpose of the combination is not to harm another, but to forward or defend the lawful interests of those who enter into it, then no wrong is committed and no action will lie, although harm to another ensues. (13) This section also briefly recounts the treatment of conspiracy to harm by the House of Lords in the milestone decisions in Sorrell, Lonrho, and Crofter Hand Woven Harris Tweed Co Ltd v Veitch. (14) Part II examines the various explanatory efforts of the House of Lords in Part I, and evaluates the explanatory capacity of the two primary justificatory theories advanced in that jurisprudence, both of which flow from the tort's focus on concerted conduct. This analysis suggests that the unanimous decision in Lonrho that conspiracy to harm was both inexplicable and immovable paved the way for judicial missteps in both England and Canada. Part III focuses on the Supreme Court of Canada's decision in LaFarge, in which Estey J united the two conspiracy torts, the effect of which has been to incorporate an incongruous motive requirement into the tort of conspiracy to use unlawful means. It also explores the House of Lords' decision in Total Network, in which Lord Neuberger used conspiracy to harm as the analogical basis for an extension in the scope of the still-independent English tort of unlawful means conspiracy. Part IV responds to the apparent conceptual emptiness of conspiracy to harm, offering an analysis that takes seriously the role played by motive in the assignment of liability for conspiracy to harm in Mogul Steamship. This analysis suggests that, at its outset, the tort arose from a now-abandoned understanding of intentionally inflicted harm without just cause or excuse as wrongful in all contexts, whether undertaken alone or in concert with others. This position has, of course, been eroded since the House of Lords decided Mogul Steamship thirteen decades ago, particularly with the decisions in The Mayor of Bradford v Pickles (15) and Allen, but there is nonetheless good reason to view conspiracy to harm, on this basis, as a relic of a distinct normative order rather than an inexplicable or arbitrary singularity.

Conspiracy to harm, on this analysis, remains an abnormal basis of liability in Anglo-Canadian tort law. As a descendant of a distinct understanding of interpersonal liability foreclosed in Allen just five years after Mogul Steamship, conspiracy to harm is, I suggest, a kind of steampunk liability, (16) a vestige of a distinct form of English private ordering that has, for the most part, disappeared. (17) While difficult to reconcile with contemporary understandings of Anglo-Canadian tort liability, it is nonetheless explicable as a component of a system of private ordering that no longer exists beyond a small collection of obscure tort doctrines. Understanding conspiracy to harm as a vestige of a distinct normative tradition should discourage future efforts to close so-called 'liability gaps' between this anomalous tort and the balance of the contemporary Anglo-Canadian law of torts, the inevitable product of which would be (even more) incoherent, unprincipled, and unjustifiable limitations on interpersonal conduct.

It bears noting, at the outset, that the account below is not an attempt to justify, in a theoretical sense, the continued presence of conspiracy to harm amongst Canadian tort doctrines. Rather, it seeks to explain the tort's existence as a basis of liability in a way that permits, and even demands, such a justification. So long as conspiracy to harm retains its long-standing categorization as an inexplicable source of tort liability, the necessity of theorizing the liability it imposes is not obvious. Having made the case for conspiracy to harm as, in some way...

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