Mr Poon is the third member of the academic staff to leave the polytechnic - which was elevated to university status in November - in relation to misconduct cases this year.

Principal lecturer Trevor Sofield was sacked and an associate head, Joseph Ruddy, agreed to resign in May after an institute inquiry into allegations of research misconduct and mismanagement in the Hotel and Tourism Management Department.

Mr Poon claimed he had been awarded a PhD in mathematics by the Columbia University in New York in 1973. Columbia is ranked in the top 10 American universities.

But Francine Brown, mathematics departmental administrator of Columbia, said they did not have a record of that degree.

However, Mr Poon was certified to have attended the Graduate Faculties of Columbia University as a PhD candidate from September 1967 to May 1971, and again from September 1972 to May 1973.

He appeared before the Hong Kong Polytechnic University's disciplinary committee yesterday morning. The decision to dismiss him was made after he was questioned about his qualifications.

It is understood Mr Poon said the Columbia University panel which interviewed him on his thesis had given him an impression that he had successfully defended the article.

At the time Mr Poon applied for the polytechnic job, he had stated only that he was a PhD candidate defending his thesis.

He later told the polytechnic his defence was successful, when in fact it was not.

By the time he was informed he had failed to get the degree, people had already begun calling him 'Dr Poon'.

The polytechnic did not verify Mr Poon's claim or ask him to produce any documentary proof because he was only applying for the post of lecturer, which did not require a PhD in 1972.

The institution yesterday said: 'Based on evidence received, a discipline committee set up to conduct necessary inquiries concluded that Mr Antonio Poon did not possess the PhD degree which he claimed to have. Mr Antonio Poon has admitted this misconduct.' It refused to disclose what prompted the inquiry but the South China Morning Post recently received an anonymous letter exposing the incident.

Institution vice-president Alexander Tzang Hing-chung said: 'The management has taken a serious attitude. Honesty is very important in the academic field.

'It is a painful decision. He has been a very good and helpful [member of] staff. The management, how ever, must act resolutely to uphold the policy and credibility of the university.' Mr Tzang added: 'Appropriate action has been taken to ensure proper record of qualifications.' But he said the checking exercise was not prompted by the incident and meant only to be a move to make improvements.

The institution did not comment on whether the matter had been reported to the police.

Mr Poon refused to comment yesterday.

Asked if Mr Poon's claim to hold a PhD had affected his promotion to senior lecturer in 1976, to principal lecturer in 1983, and to the $70,000-a-month department head last year, Mr Tzang said he could not verify the facts at the moment because the promotions were 'a long time ago'.

He said appointment as a department head was not a promotion but the imposition of additional administrative duties on a staff member.

But a mathematician said academic qualifications were important in determining promotion in the basic science discipline.

A colleague of Mr Poon said in disbelief: 'He has good administrative skills and a sound mathematics foundation.' Another colleague said: 'It is regrettable. But educators should have high moral and educational standards and a publicly funded institution needs to be accountable to the taxpayers by recruiting the best qualified candidates.' Students at the department were also shocked by the dismissal of Mr Poon.

'He seems to be a very serious person. But, as a department head, he is good because he has enhanced the computer facilities for us,' a third-year student said.

There are about 200 undergraduate students and 40 academic staff in the department.