Ofsted chief inspector Sir Michael Wilshaw has called for urgent action to plug the flood of teachers leaving the UK to teach abroad – fuelled by a “worldwide boom in international schools”.

A Schools Week investigation in September revealed that around 100,000 full-time teaching staff from Britain left to teach abroad in 2014-15. It was more than the number of teachers who qualified through a university PGCE route in the same year.

Sir Michael, writing in his monthly blog today, highlighted these figures, asking if it is “fair the offspring of overseas oligarchs are directly benefiting from UK teacher training programmes at the expense of poor children in large parts of this country?”

Schools Week revealed the number of teachers leaving the UK to teach abroad

He said a worldwide boom in international schools – some set up by prestigious UK institutions – is fuelling the exodus.

Sir Michael said the lure of tax-free salaries and sunnier climates is contributing to a teacher “brain drain” from the country that is threatening to “undermine the well-intentioned reforms to school structures, curricula and assessment regimes.”

He said the number of “overseas franchises” had risen from 29 to 44 in two years, with more campuses due to open.

He also highlighted International Schools Consultancy figures which show the number of international schools is projected to double to more than 15,000 by 2025.

“It would seem that my plea of a couple of years ago for our top independent schools to put more effort into supporting the education system closer to home – “more Derby, less Dubai” as I put it then – has not been heeded.”

But Barnaby Lenon, chairman of the Independent Schools Council, said it is wrong to imply overseas expansions are the cause of shortages, he instead pointed to too few trainees and those leaving the profession early.

Chris King, chair of the Headmasters’ and Headmistresses’ Conference and headmaster of Leicester Grammar, also disputed the claim independent schools have neglected the UK’s education system, saying schools do a “great deal to help both Derby and Dubai”.

That means Barnsley not Bangkok

But Sir Michael is now again urging the government to consider “golden handcuff” payments so teachers start in classrooms within areas they are most needed, and are “kept in the state system that trained them”.

“As far as I’m concerned, that means Barnsley not Bangkok, Doncaster not Doha, and Kings Lynn not Kuala Lumpur.”

It is an idea that has traction from other in the sector, too. Leora Cruddas, director of policy at the Association of School and College Leaders (right), said more can be done to incentivise teaching.

“We would suggest that government undertakes to write off, over a period of time, the undergraduate tuition fees of students who become teachers, as long as they remain in the state system in this country during that period.”

A critical National Audit Office investigation into teacher recruitment published this month accused the Department for Education (DfE) of not doing enough to train new teachers.

It also revealed the department hadn’t met its teacher recruitment target for the past four years – despite an annual £700 million spend.

But the DfE has maintained its stance that teaching is an attractive career choice – far from being in crisis.

A spokesperson said: “It is disingenuous to suggest our approach is not working – despite the challenge of a competitive jobs market, the proportion of trainee teachers with a top degree has grown, faster than in the population as a whole, and there are more teachers overall.”

They said the number of former teachers returning to the classroom has increase year-on-year, and highlighted research showing the number of teachers leaving the profession to work abroad is only one per cent. But added: “But we are determined to continue raising the status of the profession.”