Carol Adams likes to measure her success at the General Teaching Council for England by the letters she receives.
In 2000, when the GTC was launched, she would regularly open letters full of expletives, or threatening to take her to the Court of Human Rights.
This autumn, when she announced her departure after seven years as chief executive, she received an anonymous retirement card. The message read simply: "from an ardent teacher".
"We were starting from scratch," Ms Adams said. "People initially objected to the whole notion of a GTC; felt that it infringed their human rights.
"But the tide is turning. Young teachers accept that there's accountability, that if you fall below a certain standard you shouldn't be allowed to teach."
Teacher accountability has been a sore point. The council has regularly been criticised for its failure to impose effective sanctions: teachers guilty of serious assault, of accessing pornography on school computers and of drinking on school grounds have all been allowed to continue teaching.
"Every case is considered individually," said Ms Adams. "Often, someone has had an unblemished career for years, then has a moment of weakness. We're not meant to be as punitive as possible. We're meant to be as close to justice as possible - what's right for that person."
She insists that the role of the GTC is not only to reprimand errant teachers, but also to provide opportunities for professional development and career advancement.
But a Mori poll, commissioned by the council this summer, found that only a fifth of teachers had a positive attitude towards it. A third were negative, and the remainder neutral.
And, while the GTC now works regularly with most teacher unions, the NASUWT maintains that the council should have only a regulatory role.
"You just have to think of more ways to engage with teachers," said Ms Adams. "But it was always going to be a long-term project."
When she retires, at the end of this month, the 58-year-old former history teacher plans to devote more time to ensuring that all children have equal access to education. She is part-time commissioner for the Commission of Racial Equality and she hopes to help other countries set up their own teaching councils.
She would also like to spend more time with her own two children, who are of university age. Her hobbies include playing the saxophone and practising salsa dancing.
"I've always had an in-tray," she said. "So it'll be nice to have some freedom. But I see the GTC as my baby. I hope it will be in the hands of someone who cares passionately about children's education."
Ms Adam's successor will be appointed early in the new year.