The District Court yesterday sentenced a new mainland immigrant to 21 months in prison for biting and breaking a thumb of a fellow bus passenger.

Handing down the sentence, deputy judge Ada Yim Shun-yee said the 35-year-old Wu Peng, a master's degree holder in economics, hadn't shown any remorse and still thought that biting the person's thumb was his only option.

Wu earned his master's degree from a university in Japan and worked as a language teacher in Hong Kong. He shifted from the mainland in October 2005.

On May 26 this year, he picked an argument with a bus driver of route 273A at Tai Ping Estate in Sheung Shui after refusing to pick up his one-year-old child and fold the pram to clear the passage for other passengers.

The heated argument culminated in a scuffle, and Wu reportedly pushed driver Wong Sheung-ling down to the ground twice.

Another passenger Li Kan-chuen (58) tried to intervene, telling Wu that Wong was right. But as Li stepped forward to help Wong, Wu attacked him and bit his thumb.

Wu said later that he hadn't bitten Li intentionally. Instead, Wu said Li's thumb was caught between his teeth as he tried to land a blow on his face.

A background report said that despite being an intellectual, Wu hadn't been able to get used to life in Hong Kong and felt discriminated against. Judge Yim said Wu had expressed all his anger and frustration in one incident.

But considering Wu had no previous criminal record, Judge Yim reduced his sentence from 30 to 21 months, and ordered that he be put under a psychologist's treatment.

Wu's lawyer had appealed for a lenient sentence, saying the defendant could only speak Putonghua and Japanese and was still new to Hong Kong's lifestyle.

The lawyer said Wu was on his way to his mother-in-law's place to drop his child and then rush off to a job interview. Wu was tense and nervous before the interview, and the argument had acted like a spark that started the fire.