Prosecutor Lily Yew told the Court of First Instance that the offence was committed when Tam took the mildly retarded woman to a motel in Wan Chai last year and they did not show up for work. The crime came to light when she told her mother she was having nightmares and feared getting pregnant.

Responding to defence counsel Albert Luk Wai-hung, who said the pair had been in love, Pang said: 'Even if the victim was having sex voluntarily, she was mentally challenged and it was doubtful she was having sex with the defendant out of true love. Our law is to protect people with incapacities - someone like the victim.'

The judge took into account Tam's clean record and guilty plea to halve the sentence from a starting point of 30 months.

Yew said the victim got to know Tam when she started working as a cleaner in the fast-food restaurant in Causeway Bay.

On the morning of March 24 last year, the victim's supervisor called her family after she failed to show up. When she returned home she told her mother that she had gone out with friends. Tam was late for work.

The woman told her family the truth on April 16 and Tam was arrested at the Lok Ma Chau checkpoint a week later.

The court heard he had been divorced twice and separated from his mainland wife in 2009.