Former law professor Tey Tsun Hang, accused of obtaining sex and gifts from one of his students, was on Friday acquitted of corruption by the High Court.

But even as he cleared Mr Tey of criminal wrongdoing, Justice Woo Bih Li had strong words for the ex-professor, saying that he was "a man without honour".

Mr Tey, 42, was not in court to hear the decision. He had chosen to serve the five-month jail term handed down by a district court that convicted him in June last year and has since been released from prison.

Justice Woo, giving his decision in a packed courtroom on Friday, said that Mr Tey had abused his position as a lecturer and had exploited law student Darinne Ko.

Pointing to three cards and a note as well as e-mail exchanges in which Ms Ko had written affectionate messages to Mr Tey, Justice Woo concluded that she was in love with him at the time.

Justice Woo said the trial judge was wrong in concluding that her intention of giving him gifts and having sex with him was because she was trying to get better grades in return.

The trial judge was wrong to equate morally reprehensible conduct with what is legally wrong, said Justice Woo.

However, Justice Woo had strong words for Mr Tey's conduct, in the way he exploited Ms Ko and the way he conducted his defence during the trial.

"Although the appellant may consider my decision has vindicated him, I vindicate him of the charges only. This court does not condone the way he abused his position," he said.