First there was the book, then the film, then talks on cruise ships.

Now Marie Stubbs, the high-profile former head, is branching out with plans to star as a troubleshooter in a television series, and launch her own fitness regime for women over 50.

The indomitable Scot, who turned 67 this week, has been in demand as a public speaker since she was called out of retirement for a stint as head of St George’s Roman Catholic school in north London.

She later wrote Ahead of the Class, a book about her experiences transforming the troubled school. It was turned into a TV film in which she was played by Julie Walters.

Lady Stubbs is to due to star herself in a documentary series called The School Fixer, in which she will try to turn around the academic performance of four failing schools in a year. Filming is expected to start later this year and broadcasts to begin in 2007.

In the meantime she has launched her own fitness regime, with a website for free tips and a regular newsletter for women who wish to follow her example.

Lady Stubbs has produced the Female Fiftyplus Get Fit campaign with Jason Paris, her personal trainer with whom she has exercised for the past two years. “I was the kind of pupil who wrote notes to get out of gym,” she said. “I naturally had one of those physiques that allowed me to eat anything, but that changes when you get to 50.

“My goals when I started exercising were the same as everyone else’s - get slimmer, get fitter, tone up.

“If you want to get a Mars bar and a pizza and giggle at pictures of me exercising, I don’t mind. But I hope there will be people who will think, ‘If that Marie Stubbs can do it, then so can I.’”

She said part of the reason for the fitness regime was that she felt there was demand among over-50s women. “I think it’s also because I can’t stop being a teacher,” she said. “It gets into your blood, it’s terrible.”

Lady Stubbs has kept busy since leaving St George’s in 2001, giving speeches about her year at the school to audiences including company directors, police officers, and MBA students at the London Business School.

She said many school staff would be astonished if they knew how eager firms were to learn from teachers’ experiences. Her most unusual assignment was as an attraction on a two-week cruise around the Mediterranean last year in which she gave speeches on education and leadership to audiences of up to 1,000 holidaymakers in the PO liner’s theatre.

“They had full-blown revues on the ship, cabaret, dancing, crafts,” she said. “So I had fierce competition. It was very tiring.”

Lady Stubbs was joined on the cruise by her husband, Sir William Stubbs, former chaiman of the Qualifications and Curriculum Association and leader of the Inner London Education Authority in the 1980s. He has also tried a number of her fitness exercises.

Through her Channel 4 series, she hopes she will help other teachers to rediscover the reasons why they joined the profession .

“It could go disastrously wrong,” she said. “I think a lot of people see me as a real nuisance and a maniac, but that’s their problem.”

Liam Humphreys, a Channel 4 commissioning editor, said Lady Stubbs had been an obvious choice for the series because she combined a no-nonsense attitude to scruffiness and misbehaviour with a desire to make pupils feel that they had ownership of their schools.

“Feisty and tough-talking, she’s been there, she’s done it,” he said. “And now she’s back.”

* michael.shaw@tes.co.uk

Stubbs’s regime

* A brisk walk is the best aerobic exercise if you’re just starting out.

Get yourself a decent pair of walking shoes and appropriate clothing.

* I perform my exercise routine in my conservatory. While not the biggest space, it’s more than adequate for the equipment I use.

* My dumb-bells are female-friendly, available in nice colours and are covered in a soft material, so are easy on the hands. Jason (my trainer) calls them girly weights.

* My trainer asked me would I like to look years younger, have better skin, feel good about myself, fit into that black dress, those favourite jeans again? Well I couldn’t say no to that, could I?

www.female-fiftyplus-get-fit.com