Human rights — Right to life — Right to equal protection — Mandatory death penalty — Whether constitutional — Whether mandatory death penalty arbitrary — Whether depriving of life in accordance with the law — Whether customary international law rule prohibiting hanging as mode of execution — Whether domestic legislation inconsistent with Singapore Constitution — Whether mandatory death penalty violating Articles 9, 12 and 93 of Singapore Constitution

Relationship of international law and municipal law — Customary international law — Prohibition against cruel and inhuman treatment or punishment — Whether specific customary international law prohibition against hanging as mode of execution — State practice — Whether sufficient evidence for customary international law prohibition against death penalty generally — Whether customary international law rule or domestic statute prevailing in event of inconsistency — Whether Singapore Constitution importing customary international law into Singapore — Treaties and customary international law — Vienna Convention on Consular Relations, 1963 — Whether stating principles of customary international law

Consular relations — Treaties — Vienna Convention on Consular Relations, 1963 — Singapore not party to Convention — Prevailing norms of conduct between States — Whether requirement of consular access before statements recorded — Whether statements admissible — Whether breach of Article 36(1) — The law of Singapore