Human rights — Right to life — Inhuman treatment and punishment — Mandatory death penalty — Whether contrary to customary international law — Whether inhuman — Constitution of Singapore — Whether prohibiting inhuman punishment — Equal protection of the laws — Whether violated by mandatory death penalty for trafficking more than specified quantity of drugs

Relationship of international law and municipal law — Customary international law — Whether part of the law of Singapore — Requirement that customary international law be adopted by the Singapore courts before forming part of Singapore law — Alleged customary international law rule prohibiting mandatory death penalty — Inconsistency with Singapore legislation

Sources of international law — Customary international law — Requirement of extensive and virtually uniform State practice — Whether rule of customary international law prohibiting the mandatory death penalty — Retention of mandatory death penalty by thirty-one States — Significance — The law of Singapore