Chris Keates's reputation was sealed long before her appointment as the first woman deputy general secretary of the National Association of Schoolmasters Union of Women Teachers a year ago.
In the 1980s, The TES described her as the woman in the "Iron Lady" mask. Then, as leader of Birmingham NASUWT, she was possibly the most powerful woman in the union. Today, there is no doubt.
Mrs Keates, 50, is amused by her hard-woman public image. "I don't think I'm formidable - but I am very committed, determined to get benefits for members and improve their conditions of service."
She is in the office by 7.30am whether it is at the union's Birmingham headquarters, just 10 minutes from her home, or its London base where she works two or three days each week.
Mrs Keates joined the Union of Women Teachers as a new history and geography teacher in 1974. "It was one of those things where you go along to your first meeting to find out what is going on and find you're on the executive," she says.
Once the UWT merged with the National Association of Schoolmasters, she rose through the ranks, becoming president of the Birmingham branch in 1983, its general secretary in 1986, and a national executive member a year later.
Her time at the helm in Birmingham coincided with industrial action during the mid-Eighties. She became known as a tough negotiator and her no-nonsense manner earned her the respect of members and those she was negotiating with - as well as that "formidable" tag.
In 1997, she was appointed assistant secretary of the NASUWT with responsibility for policy co-ordination. She applied to take over from Nigel de Gruchy as general secretary. When the job went to his deputy, Eamonn O'Kane, she applied for his post and got it.
She enjoys spending her spare time with her family - Charlotte, 17, Toby, 10, and her husband Les Lawrence, an IT consultant and a Conservative councillor. When they moved in together, their political divide made the headlines. "It's never caused any problems for us," said Mrs Keates. "His Labour colleagues on the council joke that in the context of New Labour, he's more to the left than them."
Her ambition is to help teachers to achieve a better work-life balance. "When I was teaching, the strains and pressures were far less than today," she said. "Teachers now have a much harder job."