Justice of the UK Supreme Court, Lord Sales, has delivered a speech to the Office of Parliamentary Counsel, examining the evolution of statutory interpretation principles. The address covered four key areas: the principle of legality, constitutional statutes, interpretative obligations under the European Communities Act 1972 and Human Rights Act 1998 and purposive interpretation approaches. Lord Sales emphasized that statutory interpretation functions as applied constitutional law, reflecting the relationship between courts, Parliament and the executive. Lord Sales outlined how courts must balance parliamentary sovereignty with rights protection while acting as faithful agents of Parliament. The speech detailed specific interpretative techniques developed by courts to maintain this balance, including the treatment of constitutional statutes and application of section 3 of the Human Rights Act.