ABSTRACT
This chapter considers the underlying basis of the doctrine of illegality, the categories of illegality and the effects of illegality on the enforcement of the relevant contract. It also considers illegal contracts under two main headings: statutory illegality and common-law illegality for the sake of simplicity. The chapter aims to Mohammed v Alaga to consider the claim for a quantum meruit, a claim that succeeded in the Court of Appeal. The overall object of the defence of illegality and the forfeiture rule is the protection of the public through deterrence from crime and other illegal conduct. The essential rationale of the illegality doctrine is that it would be contrary to the public interest to enforce a claim if to do so would be harmful to the integrity of the legal system. Illegality cases were to be resolved by the application of rules of law; any approach which required consideration of policy issues would render the law too unpredictable.
