Peter Saunderson, who retired as principal teacher of science at St David’s High in Dalkeith in June 2006, pleaded guilty at a General Teaching Council for Scotland hearing last week to making “inappropriate remarks” and “unacceptable physical conduct” towards female pupils as young as 13.

Eight girls made complaints about Mr Saunderson after an investigation was launched by the school’s head, sparked after a parent complained that Mr Saunderson had called her daughter “beautiful” in front of the class.

Other girls reported similar incidents, saying Mr Saunderson had spoken quietly into their ears and told them they were beautiful.

Mr Saunderson also told a girl that she was just like her mum, “only interested in boys”.

To a girl who was getting something out of a drawer, he said to the rest of the class: “I like a woman on her knees”. Several girls claimed he had looked inappropriately at their “chest area”, pretending to read the lettering on the front of their tops.

One girl said he had commended her “nice hand action” when she was shaking a test tube. “She was humiliated by that, because the rest of the class burst out laughing realising what was intended by it,” said GTCS solicitor Robbie Burnett. “She took it, as did the others, that he was referring to masturbation.”

Mr Saunderson admitted all the charges. But his solicitor Andrew Gibb argued that, while the comments were “crass” and would have been better left unsaid, they were made in a “jocular manner”.

He described Mr Saunderson as a popular teacher and produced a series of cards from pupils. One urged him never to lose his “mad” sense of humour; another said he had been a “positive source” of advice and “more than a chemistry teacher”. He was the “soundest” and “grooviest” of all the science block teachers, said a third card. Another said he knew “how to have a laugh”.

Mr Gibb stressed that Mr Saunderson had an unblemished record spanning 30 years.

However, Mr Burnett argued that, while Mr Saunderson might have wanted to be “friendly” with the pupils, he had crossed the line.

The GTCS disciplinary sub-committee said in its judgment: “The comments made regarding a pupil’s mother, and the implicitly sexual references and the humiliating effect of such comments on the pupils concerned, carried considerable weight with the sub-committee.”

Emma Seith emma.seith@tes.co.uk.