The appropriate test for identifying a restraint of trade has long troubled the courts. In Peninsula Securities Ltd v Dunnes Stores, the United Kingdom (“UK”) Supreme Court overruled a decision of the House of Lords that had stood for more than fifty years and adopted the ‘trading society’ test which had been put forward in a minority judgment of the House of Lords decision. Not long after this notable development, in Quantum Actuarial v Quantum Advisory, the English Court of Appeal found that the trading society test was not comprehensive as it could not apply to novel or unique provisions. The trading society test is also open to criticism for being vague and unhelpful. It is, however, supported here for its broad perspective, flexibility and synergy with the competing policies at stake: freedom to contract and freedom to trade.

In recent years, courts in the U.K. and Australia have decided a number of cases_x000D_ involving the concept of illegality,2 or ex turpi causa non oritur actio.3 Several_x000D_ of these cases have focused specifically on the branch of illegality relating to joint_x000D_ illegal enterprises. Although courts in both jurisdictions have always shown greater_x000D_ willingness to refuse claims which involve joint participants in criminal ventures_x000D_ than those which do not, the actual basis for the refusal of such claims has been_x000D_ uncertain - with some judges taking the view that the very nature of the enterprise_x000D_ negates the duty of care and others concentrating on whether it is impossible to_x000D_ establish an appropriate standard of care between joint wrongdoers. This uncertainty_x000D_ was resolved in Australia by the decision of the High Court in Miller v. Miller,4 which_x000D_ rejected as artificial the "impossibility of setting a standard of care" approach, and_x000D_ effectively reverted to an approach based on duty. Given that the High Court of_x000D_ Australia has always been something of a trail-blazer where the law on joint illegal_x000D_ enterprises is concerned, the case gave rise to understandable speculation about the_x000D_ possibility of courts in other jurisdictions following suit.