The illegality defence is an important element of private law, but its operation has been unpredictable. In Patel v Mirza, the Supreme Court opted for a flexible approach, which does not increase predictability. This approach was recently confirmed in Henderson v Dorset Healthcare University NHS Foundation Trust and Stoffel & Co v Grondona. I propose a principle to guide the application of the illegality defence in tort: namely, the claim fails for illegality if the claimant's harm is the ordinary result of the claimant's wrongdoing. It is argued that the guiding principle: (i) substantially explains the case law; (ii) is normatively defensible; and (iii) makes the defence much more predictable.

中文翻译：

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什么时候违法是侵权的抗辩？

非法抗辩是私法的重要组成部分，但其运作一直难以预料。在帕特尔诉米尔扎，最高法院选择了一种灵活的方法，它不会增加可预测性。这种方法最近在亨德森诉多塞特医疗大学 NHS 基金会信托和Stoffel & Co v 格隆多纳. 笔者提出一个原则来指导侵权行为中非法抗辩的适用：即，如果索赔人的损害是索赔人不法行为的一般结果，则索赔不成立。有人认为，指导原则： (i) 充分解释判例法；(ii) 在规范上是可辩护的；(iii) 使防守更加可预测。