SINGAPORE - A 40-year-old man who drove a drunk woman back to his home from nightspot Zouk and had sex with her while she was unconscious was on Tuesday (July 4) found guilty of abduction and rape.

The High Court rejected Ong Soon Heng's version that the woman - then a 22-year-old undergraduate working as an intern at his friend's food and beverage company - was in a state to consent to having sex with him on July 24, 2014.

Judicial Commissioner Aedit Abdullah noted that surveillance video from the club clearly showed that the woman was unconscious at about 4am. This was supported by the woman's co-worker as well as staff at the club.

He also accepted evidence from Institute of Mental Health psychiatrist Guo Song, whose blood alcohol content calculations showed that the woman was unconscious between 4am and 6.30am, when her boyfriend found her in a stupor at Ong's Hume Heights home after tracking her down using an iPhone app.

Tests showed the woman had 62mg of alcohol per 100ml of blood at 12.45pm that day.

Dr Guo estimated her blood alcohol content was between 210.50mg and 254.50mg per 100ml of blood when she was at Ong's home and she was highly unlikely to have had consensual sex at the time.

The defence had taken issue with Dr Guo's calculation, arguing that he had not taken into account factors such as gender. But the judicial commissioner said he was satisfied that the calculation was proper and justified. He added that defence psychiatrist's evidence was that the woman was probably unconscious between 4am and 6.30am.

The woman being unconscious at the time was strongly supported by the testimony of her boyfriend, father and a police officer who saw her at 11am that day, he noted. "Given her state as depicted, it beggared belief that the accused could have woken her up soon after leaving the club," said the judicial commissioner.

As for Ong's claims that he was in a relationship with the woman, the judicial commissioner said even if this was so, "the existence of any such relationship could not overcome the overwhelming evidence of the condition of the complainant, which ruled out consent".

He noted that the evidence did not show that there was in fact any intimate relationship between Ong and the woman.

He said the evidence did not establish that Ong, who was training to be a bunker surveyor, had deliberately plied the woman with drinks at the club.

"But I do find the accused had exploited the complainant in a situation of vulnerability by taking the opportunity while she was drunk to move her to his residence and there sexually assaulted her."

The case has been tentatively adjourned to September for sentencing arguments.

Deputy Public Prosecutor Sellakumaran told the court that the prosecution will also be making submissions on compensation for medical bills, an unusual move that he said was "the first time in the High Court, to my knowledge".

The maximum punishment for rape is 20 years in jail and caning or a fine. The maximum punishment for abduction is seven years in jail and caning and a fine.