Only last year the school nominated him as one of its two most outstanding teachers in the 2000 Teachers Commendation Scheme, and he was presented with an award in January.

But last month a psychologist granted him five months' stress-related sick leave.

Yeung was found unconscious outside Mei Wai House, Mei Lam Estate, shortly after 9.30pm on Thursday. Only minutes earlier he had been seen sitting on the railings on the 34th floor of the public housing block in Sha Tin. He was declared dead at Prince of Wales Hospital.

Yeung had lived with his wife and daughter in Sha Tin.

Yesterday, Yeung's boss described him as 'well-liked, devoted and hardworking'.

Principal Li Shing-sun said: 'Everybody at the school is shocked. We are still in a state of disbelief. Mr Yeung told me last month that he was unwell and that he had been suffering tremendous stress.

'He was hardworking, polite and very keen to help. He was very well-liked by students and had a wonderful relationship with other teachers and myself.'

As an administrative teacher, Yeung taught fewer sessions than his colleagues - 27 instead of 35 - but had more supervisory duties.

Mr Li declined to say if his death was linked to his workload. 'He had more responsibilities but he didn't have more work than other senior teachers.'

A third-former at the school, Simon Lam, 14, said: 'Mr Yeung was devoted to his students. We are all very sad to learn the bad news.'

Yeung's widow, Yau Lai-ying, 42, told police her husband had complained of stress before the beginning of the new school year. She told officers he had been on sick leave.

According to the school's Web site, Yeung was also chairman of the school's general affairs committee and a Putonghua subject officer. He was also an elected member of the parent-teacher committee and helped to organise teacher-training at the school.