R v Secretary of State for Foreign and Commonwealth Affairs, ex p Rees-Mogg was an English legal case in which Times journalist and life peer William Rees-Mogg, challenged the legality of the Maastricht Treaty by judicial review. The case was based on Rees-Mogg's call for a declaration that by ratifying the Treaty on the EU, the Government transferred certain prerogative powers without statutory authority. The case is notable for its liberal approach to the question of locus standi in judicial review cases.