R v Secretary of State for Foreign Affairs, ex p Lord Rees-Mogg  QB 552
Established the legality of the Government signing an international treaty which did not alter national laws, and thus did not impede upon Parliament’s sovereignty.
The claimant, Lord Rees-Mog, was a noted journalist and life peer of the House of Lords, who sought judicial review on the legality of the defendant’s signing of the Maastricht Treaty, which recognised Britain’s joining of the European Union. The claimant’s submission was that as Parliament was sovereign in Britain, it could not reduce or transfer certain powers (for instance regarding some social policies) without statutory authority, which Lord Rees-Mog did not believe had been satisfied as Parliament had not directly approved the Treaty’s signing.
Whether the signing of the Maastricht Treaty operated to illegally curtail the Crown’s prerogative.
The Court declined to give judicial review, finding that the European Communities (Amendment) Act 1993 described a process for protocol ratification which Parliament had approved. Moreover, Lloyd LJ commented that ‘It is axiomatic that Parliament alone can change the law… treaty-making power is part of the Royal Prerogative’. Further, the content of the Treaty would not operate to alter the content of any domestic British laws, and thus the matter did not impact Parliament’s legislative sovereignty.
Further notable here is that the Court’s willingness to hear the case displays the adoption of a flexible and expansive understanding to lex loci in regards to judicial review, whereby a party who wishes to bring a claim ought be able to demonstrate sufficient standing of connection to the case.