Ex turpi causa non oritur actio

Ex turpi causa non oritur actio (Latin "from a dishonorable cause an action does not arise") is a legal doctrine which states that a plaintiff will be unable to pursue legal relief and damages if it arises in connection with their own tortious act.[1] Particularly relevant in the law of contract, tort and trusts,[2] ex turpi causa is also known as the illegality defence, since a defendant may plead that even though, for instance, he broke a contract, conducted himself negligently or broke an equitable duty, nevertheless a claimant by reason of his own illegality cannot sue. The UK Supreme Court provided a thorough reconsideration of the doctrine in 2016 in Patel v Mirza.[3]