Activists hold placards in protest at the impending execution of Nagaenthran K. Dharmalingam, sentenced to death for trafficking heroin into Singapore but diagnosed as intellectually disabled, in Kuala Lumpur, Malaysia on Wednesday. They said the execution of Nagaenthran would be a violation not only of international treaties but also of the Singapore constitution. Photo: AFP

A Singapore court rejected on Tuesday an appeal against the execution of a Malaysian convicted of drugs smuggling, dismissing an argument put forward by his legal team that he should be spared because he was mentally impaired.

Nagaenthran Dharmalingam has been on death row for more than a decade for trafficking about 42.7 grams of heroin into Singapore, which has some of the world's toughest narcotics laws.

His plight has attracted international attention with a group of United Nations experts and British billionaire Richard Branson joining Malaysia's prime minister and human rights activists to urge Singapore to commute his death sentence.

Dharmalingam's lawyer Violet Netto had objected to presenting her client's prison medical records at the last hearing, citing confidentiality, and instead requested an independent psychiatric review.

But at Tuesday's hearing Chief Justice Sundaresh Menon said the bid to prevent the disclosure of medical reports was unreasonable and there was no admissible evidence showing any decline in his mental condition.

The court also dismissed the request for an independent psychiatric review.

"The appellant has been afforded due process under law, and it is not open to him to challenge the outcome of that process when he has put nothing forward to suggest that he does have a case to be considered," the five-judge panel said in its ruling.

Dharmalingam, who was wearing a purple prison uniform, did not appear to show any reaction to the ruling.

M Ravi, Dharmalingam's former lawyer who has continued to assist in the case, told reporters that the Malaysian had exhausted legal options to escape the death penalty. It was not immediately clear when the execution would be carried out.

Reuters