SINGAPORE — The highest court here yesterday threw out an appeal from a man convicted of having paid sex with an underage escort, exhausting his legal avenues to challenge his conviction.

In dismissing Spencer Gwee Hak Theng’s application, the Court of Appeal agreed with the prosecution that Gwee was attempting to argue the facts of his case by presenting them as questions of law in the interest of the public.

Deputy Public Prosecutor Terence Chua had argued that Gwee’s application was “wholly unmeritorious”, consisting of questions of fact “masquerading” as questions of law, “disingenuously attempting to mask what is in effect a relitigating of his case” — which has already been aired in the courts twice.

Gwee, a former public prosecutor who left the legal service in the 1980s, had been sentenced to four months’ jail in July last year, for paying a then-16-year-old Vietnamese girl S$300 for sex on July 19, 2011.

Gwee, 61, had challenged the conviction, claiming his hotel room booking that night was made because he had been out drinking.

However, the High Court upheld his conviction and sentence, finding his account “improbable”.

Gwee’s lawyer Senior Counsel Chelva Rajah had argued for three questions to be referred to the Court of Appeal. One was whether there is a minimum procedural safeguard to ensure the fair identification of offenders through photographs by a witness.

Another was whether the prosecution must prove the age of a victim using the best evidence available, such as through a birth certificate.

The third was whether the Court of Appeal is obliged to consider whether the guilt of an accused person has been proven beyond reasonable doubt, even when it is not persuaded that the trial judge had erred in his findings.

DPP Chua said Gwee and other men had been identified by the minor through telephone numbers stored in her mobile phone and the police showed her photographs belonging to the subscribers of the phone numbers, merely for confirmation.

He also argued that it was “blindingly obvious” that best evidence has to be shown to prove age — Gwee was in fact trying to question whether the district judge in his case had put too much weight on using the minor’s passport as proof of her age.

This point has already been settled and Gwee’s question was “a blatant attempt at disguising a back-door appeal”, DPP Chua said.

As for whether there is grounds for reversal by an appellate court, there was no controversy over the law, DPP Chua said.

The prosecution needs to prove guilt beyond reasonable doubt before there is a conviction and the appellate court is empowered to reverse or set aside a finding if it was wrong in law or against the weight of the evidence.

Delivering the Court of Appeal’s decision yesterday, Judge of Appeal Chao Hick Tin said the appellate judge in the High Court had “clearly considered the evidence” in the case and was also aware that he could set aside the conviction if the conditions were met.

Gwee will start serving his prison sentence next Friday.