Like fraud, conspiracy is not an allegation that should lightly be made: Hughes v Western Australian Cricket Assn Inc [1986] FCA 357; (1986) 69 ALR 660 at 700 (Toohey J).
Conspiracy is the agreement of two or more persons to do an unlawful act, or to do a lawful act by unlawful means. Historically, there are two kinds of conspiracy, the elements of which are distinct:
(1) an 'unlawful means' conspiracy in which the participants combine together to perform acts which are themselves unlawful; and
(2) a combination to perform acts which, although not themselves unlawful, are done with the sole or predominant purpose of injuring the claimant.
See Bullen & Leake & Jacob's Precedents of Pleadings, Vol 2, 15_th_ edn, Sweet & Maxwell, London, 2004, at [50-01]; McKellar v Container Terminal Management Services Ltd (above) at [135] - [154].
Bullen & Leake identifies the necessary elements in an action in conspiracy at [50-01.1]:
The claimant must plead and prove the following necessary elements:
(i) a combination or agreement between two or more individuals (required for both types of conspiracy);
(ii) an intent to injure (required for both types of conspiracy but must be shown as the sole or predominant purpose for type (2) above);
(iii) pursuant to which combination or agreement and with that intention certain acts were carried out;
(iv) resulting loss and damage to the claimant.
A conspiracy can be proved without evidence of an express agreement. A court is entitled to have regard to the overt acts pleaded, and to infer from those acts that there was an express agreement to further the common object of the combination. All of those said to be parties to the conspiracy should be sufficiently aware of the surrounding circumstance, and share the same object, for it properly to be said that they are acting in concert.
'Unlawful means' includes crimes and tort and breaches of statutory provisions: Trindade & Cane, The Law of Torts in Australia, 3_rd_ edn, Oxford University Press, Melbourne, 1999 at p 230. A person is using unlawful means if they are doing an act which they are not at liberty to commit: Dresna Pty Ltd v Misu Nominees Pty Ltd [2004] FCAFC 169. It is not open to a party to plead as an alternative to a substantive cause of action already pleaded the tort of conspiracy to commit the substantive wrong, nor can there be a common law conspiracy to contravene the TPA outside the form of conspiracy expressly provided for in s 75B(1)(d) of the TPA: McKellar (above) at [195] and [197]. But the first respondent has not taken any objection to the ASC on this account, hence these matters can be put to one side.
The tort requires an intention to injure. As Kiefel and Jacobson JJ observed in Dresna Pty Ltd v Misu Nominees Pty Ltd (supra, at [7]) an agreement to do an unlawful act that results in damage to another party is not the same as a conspiracy to injure that party. In order to prove a conspiracy a claimant must show that the wrongful act complained of was done with a design of injuring the claimant and that it did so. According to their Honours, a conspiracy could be directed not only at a particular individual, but also at a class, in the sense of all members of the class. Their Honours went on to say (at [123]) that the test for an action in conspiracy is: 'what was the object of those combining when they acted as they did'. They must have acted in order that, not with the result that, the claimant should suffer damage.