What Is a Conspiracy?
In Canada, Two Types of Civil Conspiracy Exist. The First Happens When Two or More People Agree to Use Unlawful Means In Efforts That Harm Another Person. The Second Type May Involve Legal Conduct Used Wrongfully For the Predominant Purpose of Causing Harm to a Target Person.
Understanding the Types of Tortious Civil Conspiracy Applicable Within the Law of Canada
When two or more people set out to do something harmful, the likelihood is that much more harm will be caused from the co-ordinated effort than would be the result where one person acts alone; and accordingly, the law of torts provides a redress against persons who cause harm via collusion.
In Canada, there are two types of tortious conspiracy that may give rise to legal proceedings. The first type of tortious conspiracy involves two or more people agreeing, or knowingly engaging in concerted behaviour, to use unlawful means that results in direct harm to a person (who then becomes the plaintiff in a civil suit alleging tortious conspiracy). The second type of tortious conspiracy involves two or more people agreeing, or knowingly engaging in concerted behaviour, to use lawful or unlawful means for the predominant purpose of causing harm to a person.
The two types of tortious conspiracy are confirmed within many cases and are very well stated within the cases of PMC York Properties v. Siudak, 2021 ONSC 1134, Dale v. Toronto Real Estate Board, 2012 ONSC 512, and Alford v. Canada, 1997 CanLII 868, wherein each followed and summarized what was said by the Supreme Court in Cement LaFarge v. B.C. Lightweight Aggregate,  1 S.C.R. 452, and wherein each case it was respectively said:
 A predominant purpose conspiracy is made out where the predominant purpose of the defendant’s conduct is to cause injury to the plaintiff using either lawful or unlawful means, and the plaintiff does in fact suffer loss caused by the defendant’s conduct. Where lawful means are used, if their object is to injure the plaintiff, the lawful acts become unlawful (see Canada Cement LaFarge Ltd. v. British Columbia Lightweight Aggregate Ltd., 1983 CanLII 23 (SCC),  1 S.C.R. 452, at pp. 471–72).
 An unlawful means conspiracy requires no predominant purpose, but is made out where the conspirators direct unlawful conduct at the plaintiff, that the defendant should know would likely cause injury to the plaintiff, and that the injury to the plaintiff does in fact occur (see Cement LaFarge, at pp. 471–72).
 There are two types of civil conspiracy. First, there is a conspiracy where the predominant purpose of the defendants is to cause injury to the plaintiffs, regardless of whether the means employed are lawful or unlawful. Second, there is a conspiracy where the conduct of the defendants is unlawful, is directed toward the plaintiff alone, and the defendants should have known that, in the circumstances, injury to the plaintiff was likely to result.
 More particularly, the elements of “predominant purpose conspiracy” require the plaintiff to establish that: (1) the defendants acted in combination, that is, in concert, by agreement or common design; (2) the predominant purpose of the defendants was to intentionally harm the plaintiff; and (3) the defendants' conduct caused harm to the plaintiff. The elements of “unlawful means conspiracy” require the plaintiff to establish that: (1) the defendants acted in combination, again that is, in concert, by agreement or common design; (2) the defendants committed some unlawful act such as a crime, a tort, or breached some statute; (3) the defendants conduct was directed towards the plaintiffs; (4) the defendants knew or ought to have known that injury to the plaintiffs was likely to occur from their unlawful act; and (5) the defendants' unlawful conduct in furtherance of their conspiracy caused harm to the plaintiff.
 There are two types of actionable conspiracy in Canada: (1) Where the predominant purpose of the defendants’ conduct is to injure the plaintiffs, whether the means used by the defendants are lawful or unlawful; and (2) where the defendants conduct is unlawful and is directed towards the plaintiffs (alone or together with others) and the defendant should have known that injury to the plaintiffs is likely to and does result. (See Canada Cement Lafarge Ltd. v. British Columbia Lightweight Aggregate Ltd., 1983 CanLII 23 (SCC),  1 S.C.R. 452 at 471-472). To be complete, the tort of conspiracy requires not only a conspiratorial agreement, but also proof that overt acts have caused damage to the plaintiffs. (See Thompson v. Coquitlam (District) (1979), 1979 CanLII 665 (BC SC), 15 B.C.L.R. 59 at 63).
The law concerning the tort of conspiracy is far from clear with respect to conduct of the defendants which is itself unlawful. The tort of conspiracy to injure is complete, as we have seen from Lonrho, supra, and the included reference to Crofter Hand Woven Harris Tweed Co. v. Veitch,  A.C. 435, where the predominant purpose of the conspiracy is to injure the plaintiff and damage in fact results. Thus the concerted action to give effect to the intent completes the tort, and if an unlawful object is necessary (assuming damages have been suffered by the plaintiff), it is but the object to injure the plaintiff. As Lord Cave said in Sorrell v. Smith,  A.C. 700, at p. 712:
A combination of two or more persons wilfully to injure a man in his trade is unlawful and, if it results in damage to him, is actionable.
The conspiracy to commit an unlawful act in the criminal law is, in this respect, differently structured. The question which must now be considered is whether the scope of the tort of conspiracy in this country extends beyond situations in which the defendants' predominant purpose is to cause injury to the plaintiff, and includes cases in which this intention to injure is absent but the conduct of the defendants is by itself unlawful, and in fact causes damage to the plaintiff. The causative problems common to the second and third submissions of the appellants will be discussed mainly in connection with the latter. Statements made in a number of English cases decided prior to Lonrho, supra, appeared to endorse this latter aspect of the tort and led the learned author of Salmond on Torts, supra, at p. 379 to conclude:
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, or the infringement of a guaranteed constitutional right.... In such a case it is irrelevant that the object of the conspirators in using those means may be legitimate. Combinations of this kind must be contrasted with what might be called "Quinn v. Leathem conspiracies," where the means are legitimate but the object is not.... Hence a conspiracy may be actionable if either the end or the means, or both, are unlawful.
Lord Diplock declined to accept this analysis, however, observing in his judgment in Lonrho, supra, at pp. 189 and 464, that:
... in none of the judgments in decided cases in civil actions for damages for conspiracy does it appear that the mind of the author of the judgment was directed to a case where the damage-causing acts although neither done for the purpose of injuring the plaintiff nor actionable at his suit if they had been done by one person alone, were nevertheless a contravention of some penal law.
As a result, Lord Diplock concluded that the House of Lords had an "unfettered choice" in defining the scope of the tort of conspiracy, and elected to limit the civil action to acts done in combination for the predominant purpose of injuring the interests of the plaintiff.
In the first form, the conspiracy is where two or more persons combine for the predominate purpose of causing injury to another. In this form of conspiracy, the unlawfulness is in the purpose of the scheme; accordingly, lawful acts become unlawful due to the intent to cause unjust injury to another person. The recent case of Hategan v. Farber, 2021 ONSC 874, very clearly cited the essential elements of the predominate purpose conspiracy wherein it was stated:
 The elements of this tort are:
(a) an agreement between two or more defendants to injure the plaintiff by specific acts;
(b) the predominant purpose of the agreement is to injure the plaintiff; (or the conduct is directed at the plaintiff and the defendant knows or should know that injury to the plaintiff is likely);
(c) the defendants act in furtherance and of their agreement to injure; and
(d) the plaintiff suffers injury as a result.
In the second form, being the tort of conspiracy to injure by unlawful means, defendants, being the alleged conspirators, may fail to appreciate the breadth of what constitutes an "unlawful means" whereas the perception may be that some form of egregious criminal act is required to constitute as the "unlawful means". However, extensive case law shows that the "unlawful means" necessary to form a tortious conspiracy is, generally, conduct that the conspirators were without liberty to commit. Accordingly, the "unlawful means" within a conspiracy to injure by unlawful means could be as egregious as a violent criminal act or could be as tame as a breach of a bylaw or even the breach of contract.
Interestingly, within many past cases, courts often looked to conduct that constituted as "unlawful means" in the context of the tort known as intentional interference in economic relations by unlawful means; however, per the Supreme Court in A.I. Enterprises Ltd. v. Bram Enterprises Ltd.,  1 S.C.R. 177, as well as the Court of Appeal in Agribrands Purina Canada Inc. v. Kasamekas, 2011 ONCA 460, the definition of "unlawful means" within a tortious conspiracy case may differ from the definition of "unlawful means" within other cases. Specifically, the Supreme Court and the Court of Appeal each respectively said:
 While the economic torts may sometimes develop along parallel lines, they have distinct historical roots and roles to play in the regulation of the modern marketplace. So, for example, this Court in Central Canada Potash accepted the proposition that a narrower definition of “unlawful means” applies in the two-party intimidation tort than in the three-party intimidation tort. This suggests that there is no general requirement of consistency in the elements of the economic torts. Similarly, the House of Lords accepted the need for different definitions of “unlawful means” for the unlawful means and conspiracy torts in Total Network. As Lord Mance put it, “[t]he two torts are different in their nature, and the interests of justice may require their development on somewhat different bases”: para. 123. This same point was made recently by Goudge J.A. on behalf of the Ontario Court of Appeal, who stated that “these two economic torts [i.e. the unlawful means and conspiracy torts] have evolved separately, and thus each ha[s] developed [its] own concept of unlawful conduct”: Agribrands Purina Canada Inc. v. Kasamekas, 2011 ONCA 460, 106 O.R. (3d) 427, at para. 34; see also R. Stevens, Torts and Rights (2007), at p. 297. Moreover, it may well be that the presence of an agreement in the tort of conspiracy justifies a different and broader definition of “unlawful means” for the tort of “unlawful means” conspiracy than is appropriate for the unlawful means tort. This is illustrated by the Court’s retention, although as an anomaly, of the so-called predominant purpose conspiracy tort on the basis that the fact of agreement between conspirators (or “combination”) could itself justify imposing liability: see, e.g., LaFarge, at pp. 471-72, per Estey J.
 Moreover, reliance on the tort of intentional interference to supply the definition of "unlawful conduct" for the tort of civil conspiracy does not recognize that these two economic torts have evolved separately, and thus each have developed their own concept of unlawful conduct.
 The court should therefore be cautious of turning away from the history of this separate evolution simply to achieve a unified theory for the economic torts. Indeed, in Revenue and Customs Commissioners v. Total Network S.L.,  2 W.L.R. 711,  UKHL 19 (H.L.), the House of Lords went further, and said explicitly that, as the torts of intentional interference with economic relations and unlawful conduct conspiracy have developed over time, the concept of unlawful conduct has a different meaning in one tort than in the other: see, for example, the speech of Lord Walker of Gestingthorpe, at para. 100.
 It is not necessary that we go that far in this case. However, rather than automatically adopting the meaning of unlawful conduct given in the intentional interference tort cases, I think the better course is to use those cases as a guide, but also consider the kind of conduct that the jurisprudence has found to be unlawful conduct for the purposes of the conspiracy tort.
 It is clear from that jurisprudence that quasi-criminal conduct, when undertaken in concert, is sufficient to constitute unlawful conduct for the purposes of the conspiracy tort, even though that conduct is not actionable in a private law sense by a third party. The seminal case of Canada Cement LaFarge is an example. So too is conduct that is in breach of the Criminal Code, R.S.C. 1985, c. C-46. These examples of "unlawful conduct" are not actionable in themselves, but they have been held to constitute conduct that is wrongful in law and therefore sufficient to be considered "unlawful conduct" within the meaning of civil conspiracy. There are also many examples of conduct found to be unlawful for the purposes of this tort simply because the conduct is actionable as a matter of private law. In Peter T. Burns and Joost Blom, Economic Interests in Canadian Tort Law (Markham, Ont.: LexisNexis, 2009), the authors say this, at pp. 167-68:
There are two distinct categories of conduct that can be described as comprising "unlawful means": conduct amounting to an independent tort or other actionable wrong, and conduct not actionable in itself. . . . . .
Examples of conspiracies involving tortious conduct include inducing breach of contract, wrongful interference with contractual rights, nuisance, intimidation, [page438] and defamation. Of course, a breach of contract itself will support an action in civil conspiracy and, as one Australian court has held, the categories of "unlawful means" are not closed.
The second category of unlawful means is conduct comprising unlawful means not actionable in itself. . . . . .
The first class of unlawful means not actionable in themselves, but which nevertheless supports a conspiracy action, is breach of a statute which does not grant a private right of action, the very instance rejected in Lonrho (1981) by the House of Lords. A common case is a breach of labour relations legislation, and another is the breach of a criminal statute such as the Canadian Criminal Code.
 What is required, therefore, to meet the "unlawful conduct" element of the conspiracy tort is that the defendants engage, in concert, in acts that are wrong in law, whether actionable at private law or not. In the commercial world, even highly competitive activity, provided it is otherwise lawful, does not qualify as "unlawful conduct" for the purposes of this tort.
Furthermore, where the unlawful means is some form of tortious conduct, the conspiracy allegation may appear as redundant and may be unnecessary. In such circumstances, upon proving the tortious unlawful means, known as a nominate tort, proving the elements of conspiracy often becomes unnecessary; yet in some circumstances, pleading conspiracy in addition to the nominate tort, and seeking to prove same, may be a worthy task. In this respect, the Supreme Court of Canada refused to strike claims for conspiracy where other torts were pleaded; see: Hunt v. Carey Canada Inc.,  2 S.C.R. 959.
An important consideration in any conspiracy action involves the doctrine of joint liability. This is especially important where certain conspirators may be better financially positioned to pay compensation as a joint tortfeasor despite merely watching from the sidelines while the wrongful acts being performed by other conspirators. In this respect, the law treats each conspirator as jointly liable regardless the level of involvement in the actual wrongs, even if the wrongs performed in furtherance of the conspiracy were unbeknownst to all conspirators; so long as any conspirators act wrongfully towards the purpose of the conspiracy, all conspirators remain as jointly liable as joint tortfeasors. This principle was described well in Bains v. Hofs, 1992 CanLII 264, where it was said:
In The Law of Torts, 7th ed. (The Law Book Company Ltd.,) c. 11, p. 229, Fleming discusses the concept of joint tortfeasors:
A tort is imputed to several persons as joint tortfeasors in three instances, viz. agency, vicarious liability, and concerted action...The critical element of the third is that those participating in the commission of the tort must have acted in furtherance of a common design. There must be 'concerted action to a common end', not merely 'a coincidence of separate acts which by their conjoined effect cause damage' (The Koursk (1924) P. 140 at 156). Broadly speaking, this means a conspiracy with all participants acting in furtherance of the wrong, though it is probably not necessary that they should realise that they are committing a tort. All persons acting in pursuance of a common end, being thus identified with each other, are accordingly responsible for the entire result and so it was laid down in 1612 that 'all coming to do an unlawful act, and of one party, the act is the act of all the same party being present' (Heydon's Case, 77 E.R. 1150 at 1151).
It is the question of concerted action that arises in the case at bar. On this issue, the learned author continues on to say at p. 230:
While the requisite degree of participation has not been precisely defined in modern decisions, there is a cogent support both in principle and ancient authority for the suggestion that it may well correspond with the description attached by the criminal law to principles in the first and second degree. This would include, besides the actual perpetrator, anyone who 'aids and abets', whether or not he actively intervenes. Knowingly assisting, encouraging or merely being present as a conspirator at the commission of the wrong would suffice.
Thus, one who knowingly assists or encourages another to commit a tort, or one who is merely present as a conspirator in the wrong that is done, is, in law, a joint tortfeasor. This principle imposes joint liability upon all conspirators even for those wrongful acts peformed subsequently by any of the conspirators even if such is without knowledge or participation to all conspirators as was stated in Claiborne Industries Ltd. v. National Bank of Canada, 1989 CanLII 183, where it was said:
In summary, as applied to the facts before this court, it must be determined whether the Bank joined forces with Black in a common design to commit unlawful acts and whether damage to the plaintiffs was foreseeable and occurred. If so, the conspirators will each be responsible for those unlawful acts of the others that are probable consequences of the original design. Finally, to extricate itself from an ongoing conspiracy, definite steps must be taken by a party to absolve itself of continuing acts in the direction of the common design.
Required Within Pleadings
In certain circumstances, the particulars of a conspiracy are without need of excessive detail; and yet in other circumstances, very detailed particulars are required. The specific requirements within a conspiracy pleading can be found within Tran v. University of Western Ontario, 2015 ONCA 295, among other cases. Of course, as is plain and obvious, persons entering into collusion with one another would avoid sitting down to write out an express agreement and detailing about an injurious plan. Additionally, conspirators, although conspiring, may individually fail to appreciate that such an improper conspiracy arrangement is occurring - which fails to negate liability. As stated by the Court of Appeal in the matter of Alleslev-Krofchak v. Valcom Limited, 2010 ONCA 557, the detailing of the particulars of a conspiracy can be implied from details within the overall pleading including the presumption of agreement arising from a "pattern of conduct" that demonstrates persons acting in concert or collusion. The sufficiency of conspiracy pleadings, including the entitlement for the court to infer a collusion, was also addressed within the case of Beaver Lumber Inc. v. Hamer, 2004 CanLII 17180. Within each of these cases it was respectively stated:
[D]escribe who the several parties are and their relationship with each other. It should allege the agreement between the defendants to conspire, and state precisely what the purpose or what were the objects of the alleged conspiracy, and it must then proceed to set forth, with clarity and precision, the overt acts which are alleged to have been done by each of the alleged conspirators in pursuance and in furtherance of the conspiracy; and lastly, it must allege the injury and damage occasioned to the plaintiff thereby.
 The statement of claim also pled conspiracy, even if obliquely, by alleging a pattern of conduct by the three appellants to remove AK as the SPM#1. The claim asserted that the defamatory statements they made about her were for the purpose of interfering with her economic relations. This is, in essence, what the trial judge ultimately found: an agreement between the appellants to defame AK in order to achieve their goal of getting rid of her.
 Finally, Valcom itself put the breach of the Valcom/ARINC subcontract in issue by arguing, in its statement of defence, that the contract entitled Valcom to deal with AK as it did. Accordingly, it was open to the trial judge, in rejecting this argument, to find that Valcom breached the contract and to use that in her analysis of unlawful means.
 All these issues were canvassed by both sides in the evidence called at trial. Counsel for the appellants essentially acknowledged as much in her closing submissions. In this court, appellants’ counsel (different from trial counsel) did not point to any prejudice said to arise from any pleading deficiency.
 Most importantly, the trial judge was alive to the weaknesses in the pleadings. However, because the matters now raised by the appellants were the subject of evidence called by both sides, she exercised her discretion to deal with them “in an effort to secure the just determination of the real matters in dispute in this litigation.” This was a four week trial involving a significant amount of detailed evidence on these matters. The trial judge was best placed to determine whether any deficiencies in the respondents’ pleading made it unfair for her consider them in addressing the unlawful means question. In all the circumstances, I see no basis to interfere with her exercise of discretion.
31 A claim for conspiracy is sustainable where the following particulars are pleaded:
(a) the parties to the conspiracy, and their relationship to one another;
(b) the agreement between the parties;
(c) the purpose or objects of the conspiracy stated precisely;
(d) the overt acts done in pursuance and furtherance of the conspiracy stated with clarity and precision; and
(e) the injury and damages occasioned to the plaintiff.
(See Bullen, Leake and Jacobs, Precedents of Pleadings, 12th Ed. (1975) p. 341; also cited in Bank of America v. Mutual Trust Co.,  O.J. No. 2662 (Ont. Master), at 3.)
32 The court is entitled to draw an inference that the defendants acted in concert in relation to an allegation of conspiracy where some information is provided with respect to the conspiracy. Specifics of various aspects of the conspiracy may not be available to the plaintiff until examinations for discovery. Defendants ought to know whether or not their actions constituted conspiracy, thereby allowing them to plead that they were not engaged in a conspiracy. It may therefore be premature to strike a claim for conspiracy at the pleading stage. (See Acronym (Cayman) Inc. v. Ontario Lottery Corp.,  O.J. No. 2702 (Ont. Gen. Div.), at 4.)
.... the requirement that it be "plain and obvious" that some or all of the statement of claim discloses no reasonable cause of action before it can be struck out, as well as the proposition that it is singularly inappropriate to use the rule's summary procedure to prevent a party from proceeding to trial on the grounds that the action raises difficult questions, has been affirmed repeatedly in the last century.
Avoiding Redundant Litigation Concerns
Defendants may argue that pleading conspiracy where unlawful means is alleged and involves underlying torts (sometimes referred to as nominate torts), the pleading of the underlying tort is sufficient and pleading of conspiracy becomes redundant and unnecessary; however, per Hunt v. Carey,  2 S.C.R. 959, as recently was cited and followed by the Court of Appeal in McHale v. Lewis, 2018 ONCA 1048, it was said that:
 In Hunt v. Carey Canada Inc., 1990 CanLII 90 (SCC),  2 S.C.R. 959, the court held that there were good reasons to allow a conspiracy claim to go to trial along with other related tort actions. At p. 989 Wilson J. observed that a conspiracy may give rise to harm of a magnitude that is greater than that of tortfeasors acting alone.
 Finally the issue of whether there was any redundancy in the claims successfully made should be left to the trial judge.
 In Hunt the court noted further at pp. 991-92:
It seems to me totally inappropriate on a motion to strike out a statement of claim to get into the question whether the plaintiff's allegations concerning other nominate torts will be successful. This a matter that should be considered at trial where evidence with respect to the other torts can be led and where a fully informed decision about the applicability of the tort of conspiracy can be made in light of that evidence and the submissions of counsel. If the plaintiff is successful with respect to the other nominate torts, then the trial judge can consider the defendants' arguments about the unavailability of the tort of conspiracy. If the plaintiff is unsuccessful with respect to the other nominate torts, then the trial judge can consider whether he might still succeed in conspiracy. Regardless of the outcome, it seems to me inappropriate at this stage in the proceedings to reach a conclusion about the validity of the defendants' claims about merger. I believe that this matter is also properly left for the consideration of the trial judge.
The tort of conspiracy consists of two forms; the conspiracy to injure by unlawful means as well as the conspiracy to injure as predominant purpose. In a conspiracy to injure as predominate purpose, the conduct causing injury may be entirely lawful; however, it is, essentially the plotting to purposely and intentionally cause harm by the use of an otherwise lawful activity that makes the conduct tortious.
The tortfeasors within a conspiracy are all jointly and severally liable for the conduct of all tortfeasors if the outcome is a foreseeable result of the original plot.
Additionally, and logically whereas written evidence of a conspiratory plot is unlikely to exist, the acting in collusion or engaging in concert may be sufficient to establish a presumption of a conspiracy agreement or intentions.