The former deputy public prosecutor who has been charged for having paid sex with an underaged prostitute, said he was never put through a formal identification parade by the police.

Instead, Spencer Gwee charged that the investigation officer had "spoon-fed" the then-16-year-old Vietnamese girl facts gleaned from him over two "general interviews" and that evidence was then put together in a "re-construction".

Gwee, 61, is alleged to have had paid sex with the girl on July 19, 2011 at Four Chain View Hotel in Geylang. He has maintained that he never met the girl until his trial nor had commercial sex before.

"I have every reason to believe that the girl identified me solely on the basis of a photo that was shown to her," he said during cross-examination by the prosecution on Wednesday morning.

"How did the photos come about? She didn't produce those photos," he said, adding that the girl "was not in a position" to contradict photos produced by the police.

But DPP Terence Chua said that Gwee's allegations that police had cherry-picked him out of a list of more than a hundred numbers - and told the girl his picture matched a number in her phone - because he was a "big fish" was "pure fantasy", as Gwee had no evidence to back the claim.

Gwee, a lawyer of some 30 years, was also asked to state whether a hotel employee who only worked the night shift and who testified to seeing him park his gold Toyota in front of the hotel that night was lying.

He replied that he was not in a position to explain the worker's evidence, but posited that the worker could have seen him parking the Toyota in the afternoon, while off-duty, as he sometimes ate in the area during the day.

He added that while he usually drove the Toyota during the day, he would switch to his BMW "virtually" every evening, and he was certain he did not drive his Toyota to Geylang that night.

The defence will call Gwee's client Mr Arthur Chew to testify on Thursday. Gwee had said he was with Mr Chew that evening between 10pm and around 11.50pm.