The outgoing leader of Britain’s most moderate teaching union can sometimes be seen wearing a gold pendant in the shape of a cannabis leaf.

Jean Gemmell thought she had bought a maple leaf. She realised her mistake when an attendant at the House of Lords spotted it and exclaimed, “Oh, you naughty girl!”, But she continued to wear it, even to meetings with ministers.

It is a perfect illustration of the phlegmatic, no-nonsense approach taken by the Professional Association of Teachers’ general secretary.

The 65-year-old has always insisted that all publicity is good publicity, even when faced with some of her members’ more off-the-wall suggestions, such as the infamous “dogs as classroom assistants” proposal, .

“Even if people don’t agree, at least they know we are out there,” she said.

This week, she addressed her final PAT conference which, apparently by a fluke, took place in Buxton, where she has a second home. Mrs Gemmell, whose first love was the stage, has produced semi-professional musicals at the Derbyshire spa town’s opera house since the 1980s. Sharp-eyed delegates could have spotted her dressed as the Statue of Liberty on posters publicising her lead role in next month’s production of Irving Berlin’s Call me Madam.

She moved to the PAT from the National Union of Teachers as a physics teacher in the early 1970s because of its unique no-industrial-action policy. But she was not an active trade unionist until she became head of Fernwood comprehensive, in Nottingham, in 1983, and decided to do something to challenge the then very male-dominated Secondary Heads Association.

That led her to apply for the job as the PAT’s senior professional officer in 1999, a role she thought would ease her into retirement. Instead, within two years she had been elected to the top job.

The school workforce agreement has been one of the highlights of Mrs Gemmell’s leadership, both because of its recognition of the role of school support staff, something she always promoted, and the extra influence it brought the association.

“It is not to do with personal aggrandisement, but being seen and recognised in high places and being on Christian-name terms with people in high places means that the PAT is known,” she said.

It was always understood that she would leave in August because another term as general secretary would take her to the age of nearly 70. But she has no intention of retiring and is already looking for another education job.

She believes her successor Philip Parkin, deputy head at Old Clee junior, in Grimsby, will face some challenges, with an ageing membership and fierce recruitment competition from rival unions.

“He has to consider whether we are sustainable as an independent organisation or whether a better way forward would be some sort of amalgamation, and if so with whom,” she said. “He needs to keep us in the public eye and promote us further, and show that we are really not as nutty as all that, though we do have some splendidly eccentric characters.

Perhaps I am one of them.”

* william.stewart@tes.co.uk