The UK runs the risk of a headteacher “brain drain”, as more school leaders take up jobs abroad, says the outgoing head of Loughborough High School.

Gwen Byrom will also end her tenure as president of the Girls’ Schools Association in January, when she moves to Bangkok to become founding principal of the Thailand capital’s new North London Collegiate School International.

She is one of a growing number of high-profile private school leaders, including former heads of Wycombe Abbey and Harrow, who are taking up posts in education outside the UK.

Ms Byrom said the shift was exacerbating the already growing shortage of teachers who are willing to step into senior roles in the UK.

“Sometimes there is sadly such a feeling of negativity surrounding teaching in the UK that people think ‘I want to be free of that’,” she told Tes.

“There are more and more of us that are heading towards retirement, and it has been hard to make headship look attractive at times.”

Asked if the UK was now facing a headteacher brain drain, she said: “I think it is a risk.”

Numerous studies have charted the growing strain on school leaders in Britain, including rising rates of stress, depression and alcohol abuse.

Meanwhile, a record number of UK independent schools are expanding overseas to meet the growing demand for British-style education, in particular in Asia and the Middle East.

More than 100 new international schools have opened this year alone, including 18 in China, 12 in Malaysia and five each in Vietnam and Thailand, according to ISC Research.

Experts say many British independent schools are seeking new ways to raise cash, as slowing domestic fee growth and rising costs squeeze their margins.

“Lots of independent schools that are doing this, they’re not doing it as a cash cow, but they’re doing it to see what they can bring back to the UK for philanthropic reasons,” said Ms Byrom.

“It’s very hard to raise the sorts of finances you need to put a significant number of children through [private] school on a ‘needs-blind’ basis.”

Ms Byrom said she had not considered moving abroad until she was asked to apply for the job with North London Collegiate, which has several overseas branches.

With five children, she said moving abroad would have been too much in the past. As it is, she and her husband are only taking their youngest son, aged 3, with them.

After seven years at Loughborough High School, Ms Byrom was enticed by the opportunity to design and build a school from the ground up. That will quite literally be the case in her new role: at present, the school has no buildings, staff, curriculum, nor anything beyond government approval.

“My interest is in how you take a British curriculum and how you take the way we understand education and transplant that in another part of the world,” she said.

“I’ve spent half my time in school saying [to students], when you leave school, amazing chances will come your way…it won’t be the thing you expect it to be, but it will be the best thing that ever happened to you.

“So when the opportunity came along, I felt I would be a bit of a fraud if I didn’t practice what I preached.”