This question has troubled lawyers for a long time, but now requires you to engage critically with the decision of the Supreme Court in Patel v Mirza. Do you think it creates more problems than it solves? Has it solved the notoriously difficult decisions in contract law discussed in this chapter? If the illegality defence were abolished, would that affect the outcome of decided cases? It is important to consider the leading cases carefully in your answer to this question, and to have a clear line of argument apparent from the outset.