SINGAPORE - A day before he was scheduled to hang on Friday (May 24), a Malaysian drug mule on death row got a temporary reprieve after the Court of Appeal granted him a stay of execution.

Pannir Selvam Pranthaman, 31, applied for his death sentence to be stayed on the basis that he intends to mount a legal challenge against the rejection of his petition for clemency to President Halimah Yacob.

On Thursday (May 23), a three-judge Court of Appeal granted his request, noting that Pannir Selvam was told of the rejection and his execution date just one week in advance.

This did not leave the prisoner much time to obtain legal advice on what options he has to challenge the rejection of his clemency plea, said Chief Justice Sundaresh Menon.

He added that Pannir Selvam's Singapore lawyers, Mr Too Xing Ji and Mr Lee Ji En, who were instructed only on Thursday, could not be expected to mount a fully developed argument in such a time frame.

CJ Menon said: "There are extremely narrow grounds upon which the clemency process may be so impugned. However, in our judgment, the applicant ought to have a reasonable opportunity to take advice on whether he can mount a successful challenge."

During the hearing, Mr Too raised questions about the "lack of transparency" of the clemency process in relation to Pannir Selvam, who was convicted of importing 51.84g of heroin in 2017.

The court heard that two letters sent to his family - one from the Istana rejecting the clemency petition and the other from the Singapore Prison Service stating his execution date - were both dated May 17.

In an affidavit, Pannir Selvam said his family had courier receipts to show that the letters were posted out on May 16.

He took issue with the sequence of events, arguing that he had been deprived of a fair clemency process.

In response, the prosecution, represented by Senior Counsel Francis Ng, submitted affidavits from the Istana, the Attorney-General's Chambers and the prisons, to set out the sequence of events.

Mr Benny Lee, principal private secretary to the President, said in his affidavit that prior to May 7, Madam Halimah had been advised by the Cabinet that the law should be allowed to take its course in Pannir Selvam's case.

On May 7, Mr Lee signed letters informing Pannir Selvam and his family that the death sentence would stand. These letters were sent to the prisons on May 14, to be forwarded to the prisoner and his family.

In a statement addressing Malaysian media reports about the case, the Ministry of Home Affairs (MHA) said the petitions were carefully considered.

The President acted on the advice of the Cabinet, in accordance with the Constitution, in not exercising the clemency power, said the statement on Thursday.

The ministry also clarified reports claiming that Pannir Selvam was unreasonably denied a certificate of substantive assistance, which might have spared him the mandatory death penalty.

"MHA would like to clarify that the decision is taken by the Public Prosecutor in his sole discretion, based on whether the offender had provided the authorities substantive assistance that leads to the disruption of drug trafficking activities in Singapore. The Public Prosecutor determined that he had not," it added.

This issue was not pursued in court by Mr Too, who focused on the clemency process.

He argued that it was still not clear when the decision was made, why the letters were post-dated, and why the decision had not been communicated earlier to his client's family.

He said his client was deprived of the time to consult a lawyer to see if there were any grounds to file a judicial review against the rejection of his clemency petition.

The court, which also comprised Judges of Appeal Judith Prakash and Steven Chong, directed Pannir Selvam to file his intended application and supporting evidence in two weeks.

The prosecution will have two weeks to respond, then both sides have another week to file written submissions, before a hearing date is fixed.

Challenges against the clemency process are rare.

In 2011, the Court of Appeal held, in the case of Malaysian drug trafficker Yong Vui Kong, that decisions on clemency are subject to judicial review only in relation to procedural lapses, and not on their merits.