A Birmingham headmistress who was at the forefront of the campaign to save the grammar school system is set to retire after two decades at the top.

During her time at King Edward VI Handsworth, Elspeth Insch has overseen major building projects and shared in her pupils’ exam triumphs.

Miss Insch has also been no stranger to the media spotlight, while at the centre of a national fight to keep grammar schools open when the system was under threat in the late 1990s.

But as staff and students prepare for another term, Miss Insch will be swapping school corridors for a cottage in the Pennines after taking retirement at the age of 63.

A new book has been penned entitled Centenary to Centenary, a love letter to the top girls’ school she says she will “cherish”.

“It is absolutely the time to go now,” said Miss Insch.

“I am now 63 so could have retired three years ago but decided to stay on because I have a great feel for the history of the school and absolutely adore the buildings, so the centenary of the school last September was going to be, for me, something very special.

“My feeling is I have got the school as far along the road as I can and in a whole variety of different ways, the buildings, staff appointments, exam results, educational initiatives in the school.”

The book touches one of the more testing times of her headship, in the wake of Labour’s landslide victory in the 1997 General Election.

It was an uncertain time for selective education across the country, with parents encouraged to trigger ballots to change admission arrangements at local grammar schools.

The Government also banned the building of any new grammars, but the campaign to scrap them petered out once parents in Yorkshire voted overwhelmingly in 2000 to leave Ripon Grammar as it was.

It was during this period Miss Insch was often called upon to be the voice of selective schooling both in the media and Parliament – role she found demanding.

She also made her feelings rather more covertly known when, disguised in an old mac, headscarf, and her father’s glasses, she attempted to disrupt a petition organised by the local arm of the Campaign for State Education.

She said: “It took a massive part of my life rising to that defence, the after hours interviews, often early in the morning or late at night, and often at the drop of a hat.

“It really was a blasted nuisance and very stressful, but also along the way, if I hadn’t felt I had to fight for the future of grammar schools, I can’t say I didn’t enjoy the media attention. But I wish it hadn’t been from a negative basis.

“I think it was fairly close to a miracle that we survived that time.

“Maybe there were people who recognised that getting rid of grammar schools wouldn’t deal with the issue of improving education.

“And then you had all the issues with academies and maybe that diverted attention from grammar schools. But I still find it amazing that grammar schools survived, although very thankful that they did.”

Miss Insch is succeed at King Edward VI Handsworth by Elisabeth Wager, who has served as her “outstanding” deputy for six years.

She will leave behind a permanent reminder of her time at the school in the form of renovated buildings, and a new library which opened in 2011 to mark the school’s centenary.

She said the highlight of her 20 years in charge has been hearing from former pupils who have gone on to success.

“It’s not always the girls who were particularly sparky or prominent in school,” she added.

“But the ones who got on with the job and you hear they have done brilliantly in university and got wonderful, interesting jobs whether in media or the fringes of politics, one who has got a job with the consulate in Nigeria and another girl who set up her own business in New York in her 20s.”

One of her most recent visitors was former head girl Sally Humphreys, now partner of Rolling Stone Ronnie Wood. “That was pretty amazing. She was the head girl when I started 23 years ago and, when she got in touch to say she wanted to visit I asked if she would ask Ronnie to come along too.”

She added: “I am in absolutely no doubt that I am making the right move on a personal level, on a professional level, and for the school.

“It has been a cracking good time.”