To obtain in civil proceedings a remedy for conspiracy, the plaintiff must establish (a) a combination of the defendants, (b) to effect an unlawful purpose, resulting in damage to the plaintiff (Crofter Hand Woven Harris Tweed Co Ltd v Veitch ([1942] 1 All ER 142 at 147, [1942] AC 435 at 440) per Lord Simon LC). The classic definition of conspiracy is that in Mulcahy v R ((1868) LR 3 HL 306 at 317): ‘A conspiracy consists not merely of the intention of two or more, but in the agreement of two or more to do an unlawful act, or to do a lawful act by unlawful means.’
— Buckley LJ. Belmont v Williams [1980] 1 ALL ER 393