Article 9 of the Constitution of the Republic of Singapore, specifically Article 9(1), guarantees the right to life and the right to personal liberty. The Court of Appeal has called the right to life the most basic of human rights, but has yet to fully define the term in the Constitution. Contrary to the broad position taken in jurisdictions such as Malaysia and the United States, the High Court of Singapore has said that personal liberty only refers to freedom from unlawful incarceration or detention.
Article 9(1) states that persons may be deprived of life or personal liberty "in accordance with law". In Ong Ah Chuan v. Public Prosecutor (1980), an appeal to the Judicial Committee of the Privy Council from Singapore, it was held that the term law means more than just legislation validly enacted by Parliament, and includes fundamental rules of natural justice. Subsequently, in Yong Vui Kong v. Attorney-General (2011), the Court of Appeal held that such fundamental rules of natural justice embodied in the Constitution are the same in nature and function as common law rules of natural justice in administrative law, except that they operate at different levels of the legal order. A related decision, Yong Vui Kong v. Public Prosecutor (2010), apparently rejected the contention that Article 9(1) entitles courts to examine the substantive fairness of legislation, though it asserted a judicial discretion to reject bills of attainder and absurd or arbitrary legislation. In the same case, the Court of Appeal held that law in Article 9(1) does not include rules of customary international law.
Other subsections of Article 9 enshrine rights accorded to persons who have been arrested, namely, the right to apply to the High Court to challenge the legality of their detention, the right to be informed of the grounds of arrest, the right to counsel, and the right to be produced before a magistrate within 48 hours of arrest. These rights do not apply to enemy aliens or to persons arrested for contempt of Parliament. The Constitution also specifically exempts the Criminal Law (Temporary Provisions) Act (Cap. 67, 2000 Rev. Ed.), the Internal Security Act (Cap. 143, 1985 Rev. Ed.), and Part IV of the Misuse of Drugs Act (Cap. 185, 2008 Rev. Ed.) from having to comply with Article 9.