Ong Ah Chuan v Public Prosecutor

Ong Ah Chuan v Public Prosecutor
Court	Judicial Committee of the Privy Council
Full case name	Ong Ah Chuan and another v. Public Prosecutor
Decided	15 October 1980 (1980-10-15)
Citation(s)	[1980] UKPC 32, [1981] A.C. 648, [1981] 1 M.L.J. 64, [1979–1980] S.L.R.(R.) 710
Case history
Prior action(s)	[1977–1978] S.L.R.(R.) 417, H.C. (Singapore) [1979–1980] S.L.R.(R.) 53, C.C.A. (Singapore)
Court membership
Judges sitting	Lord Diplock, Lord Keith of Kinkel, Lord Scarman and Lord Roskill.
Case opinions
Provisions in the Misuse of Drugs Act 1973 (No. 5 of 1973) creating a rebuttable presumption of drug trafficking and imposing a mandatory death penalty for certain trafficking offences do not violate Article 9(1) or Article 12(1) of the Constitution of Singapore.

Ong Ah Chuan v Public Prosecutor is a landmark decision delivered in 1980 by the Judicial Committee of the Privy Council on appeal from Singapore which deals with the constitutionality of section 15 of the Misuse of Drugs Act 1973 (No. 5 of 1973) (now section 17 of the Misuse of Drugs Act (Cap. 185, 2008 Rev. Ed.)) ("MDA"), and the mandatory death penalty by the Act for certain offences. The appellants contended that the presumption of trafficking under section 15 of the MDA violated Article 9(1) of the Constitution of the Republic of Singapore (1980 Reprint) (now the Singapore Constitution (1985 Rev. Ed., 1999 Reprint)) and that the mandatory death penalty was arbitrary and violated Article 12(1) of the Constitution.

Dismissing the appeal, the Privy Council clarified several issues of Singapore law. It explained that the word law in Article 9(1) includes fundamental rules of natural justice. The court also held that Article 12(1) does not prohibit differentiation between classes of people, but requires that like should be compared with like. It also laid out the "reasonable relation" test to determine if legislation is in breach of Article 12(1).

Ong Ah Chuan has been referred to in subsequent cases. In some of them, attempts have been made to argue that certain legal principles are fundamental rules of natural justice, and thus constitutionally protected by Article 9(1). There has also been academic discussion concerning whether fundamental rules of natural justice enable the courts to examine the substantive fairness or reasonableness of laws. The ruling in Ong Ah Chuan that the mandatory death penalty is constitutional has not been followed in later Privy Council decisions. These cases were distinguished by the Singapore Court of Appeal in Yong Vui Kong v. Public Prosecutor (2010) on the basis that the constitutions involved in those cases contained express prohibitions against inhuman or degrading punishment or treatment, which the Singapore Constitution lacks.

The reasonable relation test applied to Article 12(1) by the Privy Council has been applied in a number of local and foreign cases. It was reformulated into a three-stage test by the Court of Appeal in Public Prosecutor v. Taw Cheng Kong (1998). The Court applied a modified version of the test to situations involving the discriminatory application of neutral laws in Eng Foong Ho v. Attorney-General (2009), and expressed the view that Article 12(1) would only be infringed in such cases where there was intentional and arbitrary discrimination, or inequalities due to inadvertence or inefficiency on a very substantial scale. The element of arbitrariness was also mentioned by the Court in Chng Suan Tze v. Minister for Home Affairs (1988) – it said a law that allows a public authority to exercise arbitrary discretionary power is in violation of Article 12(1).