The  appellant,  Yong  Vui  Kong  (“the Appellant”),  was  convicted  of  trafficking  in  47.27g  of diamorphine,  a controlled  drug,  and  sentenced  to  death  (see Public Prosecutor  v  Yong  Vui  Kong[2009]  SGHC  4).  He  appealed against  the  conviction and  the  sentence,  but  later  withdrew  that appeal. Four days before the sentence was to be carried out, he filed Criminal Motion No 41 of 2009(“CM 41/2009”) seeking leave to pursue his appeal. This court granted him leave to do so (see YongVui Kong v  Public  Prosecutor [2009] SGCA 64). In the present proceedings, the Appellant’s counsel,Mr  M  Ravi ("Mr Ravi"), has confirmed that the Appellant is appealing against only his sentence, and not his conviction.

The  general  issue  in  this  appeal  is  whether  the mandatory  death  penalty  (“the MDP”)  ispermitted by the Constitution of the Republic of Singapore (1985 Rev Ed, 1999 Reprint). The specificissue  is  whether  the  MDP imposed  under  certain  provisions  of  the  Misuse  of  Drugs  Act  (Cap  185,2001 Rev Ed), in particular, is permitted by the Constitution of the Republic of Singapore.

Court ruling:

59  We agree that domestic law, including the Singapore Constitution, should, as far as possible, be interpreted consistently with Singapore’s international legal obligations. There are, however, inherent limits  on  the  extent  to  which  our  courts  may  refer  to  international human  rights  norms  for  this purpose. For instance, reference to international human rights norms would not be appropriate where the  express  wording  of  the Singapore  Constitution  is  not  amenable  to  the  incorporation  of  the international norms  in  question,  or  where  Singapore’s  constitutional  history  is  such  as to  militate against the incorporation of those international norms (in this regard, see further [61]–[72] below). In such circumstances, in order for our courts to give full effect to international human rights norms, it would be necessary for Parliament to first enact new laws (as the drafters of the UDHR hoped States would do) or even amend the Singapore Constitution to expressly provide for rights which have not already been incorporated therein. Both of these measures are, as Lord Bingham observed in Reyes at[28]  (reproduced  in  the  preceding  paragraph),  well within  the  prerogative  of  a  sovereign  State.  In short,  the  point  which  we  seek to  make  is  this:  where  our  courts  have  reached  the  limits  on  the extent to which they may properly have regard to international human rights norms in interpreting the Singapore Constitution, it would not be appropriate for them to legislate new rights into the Singapore Constitution under the guise of interpreting existing constitutional provisions.

60 Where the Singapore Constitution is concerned, we are of the view that it is not possible to incorporate  a  prohibition  against inhuman  punishment  through  the  interpretation  of  existing constitutional provisions (in this case, Art 9(1)) for two reasons.

61  First, unlike the  Constitutions of the Caribbean  States, the  Singapore  Constitution does not contain  any  express prohibition  against  inhuman  punishment.
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64 The  second  and  more  important  reason  why  it  is not  possible  to  interpret  the  Singapore Constitution as incorporating a prohibition against inhuman punishment is that a proposal to add an express  constitutional  provision  to  this  effect  was  made to  the  Government  in  1966  by  the constitutional  commission  chaired  by  Wee  Chong Jin  CJ  (“the  Wee  Commission”),  but  that  proposa lwas ultimately rejected by the Government.

https://www.supremecourt.gov.sg/docs/default-source/module-document/judgement/2010-sgca-20.pdf