Former deputy public prosecutor Spencer Gwee Hak Theng, charged with having paid sex with a minor, took the stand on Tuesday morning.

This after District Judge Toh Yung Cheong said that the prosecution had proven that Gwee had a prima facie case to answer to.

The 60-year-old is accused of paying an underaged Vietnamese prostitute $300 for sex in July 2011 at Four Chain View hotel in Geylang.

His lawyer, Subhas Anandan, had earlier submitted to the court that Gwee had no case to answer, as the state had failed to prove that the girl was below 18 at the time she met Gwee. This was because the police officer who cracked the vice syndicate she was working for failed to seize her IC - which she then claimed she lost - and the court had to rely on whatever she said her age was.

But Deputy Public Prosecutor Terence Chua pointed out that the girl's passport had been submitted as primary evidence, and there had been no doubts raised about its authenticity.

Judge Toh agreed, and said the victim had testified to her age, and it was not "merely hearsay".

On the stand, Gwee denied ever having met the girl, or ever having paid for commercial sex before. He told the court the two SMSes he sent to her phone on the July 2011 day he allegedly had paid sex with her were to ask who the number belonged to, as he had received missed calls from the number he claimed he did not recognise.

Gwee said: "As a lawyer, you get a lot of calls. You don't want to call them back, so you just SMS them: 'who are you?'". The lawyer, who was a DPP for seven years, added that she might have got his number from other girls, as he had lent his phones out to waitresses before for them to make calls home "out of sympathy".

Gwee, a lawyer of nearly three decades, is the last of 11 men charged in relation to a vice syndicate operated by a couple in Geylang.