'He who comes to Equity need not do so with clean hands?' illegality and resulting trusts after Patel v Mirza, what should the approach be?

In Patel v Mirza, the UK Supreme Court attempted to resolve the problems in the law of illegality by overruling the reliance principle in Tinsley v Milligan. However, the Court was divided 6: 3 on the approach to be taken. Whereas the majority favoured a discretionary approach, the minority adopted a restitutionary approach. Which approach is preferable? This article assesses the strengths of both approaches by examining whether they can resolve the problems of the reliance principle; whether they are normatively sound; and their capacity to resolve a contemporary problem: illegality and small houses in Hong Kong.