A head of department who stopped 84 pupils gaining GCSEs because he failed to send their marks to an examination board has been found guilty of unacceptable professional conduct.
Victor Grigson, who taught at Connaught school for girls in Leytonstone, east London, was given a reprimand which will remain on his record for two years.
The pupils' work has not been recovered and they have never received marks.
Mr Grigson, who has 25 years' teaching experience, was sacked from the school in October 2004 and is now working as a supply teacher in a unit for children who have been excluded.
He admitted to a disciplinary committee of England's General Teaching Council that he had failed to send in the marks.
Mr Grigson said he was not cut out for the role of head of the school's ICT department and that he realised now that he should have asked for help.
"I know I made mistakes and can't say why I didn't ask for help," he said.
"I would never knowingly do any action that would impact so badly on any pupil and I would never want it to happen again."
The disciplinary hearing was told that Mr Grigson failed to meet a deadline in May 2004 to dispatch assessment and coursework mark sheets for the 107 GCSE pupils and nine candidates sitting computer literacy and information technology (CLAiT) qualifications.
The school, which has 600 pupils, was unaware of the problem until it was contacted by the exam board two months later. Mr Grigson was then asked to send the documents, which he failed to do, telling colleagues that he was too busy and was preparing to go on holiday.
He failed to respond to further requests from the exam board for sample marks and students only discovered that their GCSE results were not available on the day results were published in August 2004.
The hearing was told that Mr Grigson gave the exam board, headteacher and other staff misleading or untrue explanations as to the progress of assessment of students' work when school resumed in September.
On one occasion, he said the coursework was in his car and on another, that he had left it at home. When the school arranged for a taxi to collect missing coursework scripts from Mr Grigson's home, only 23 of the 107 submitted by GCSE pupils were found and he was subsequently suspended.
A formal investigation was launched by the school into the lack of coursework papers for the remaining 84 GCSE candidates and all nine CLAiT students.
None has been recovered. As a result, the affected students did not gain their qualifications.
The GTC ruling followed a private session of the hearing which considered Mr Grigson's personal circumstances. None of the evidence in private was disclosed.