Heads say the job involves too much paperwork

Geoff Lucas, general secretary of the Headmasters' and Headmistresses' Conference, said sabbaticals could involve travel or work experience.

This could stop heads retiring early because of stress, he added.

But the government said decisions over sabbaticals were "best made by individual schools".

Morale

The HMC, which represents 240 independent schools, carried out a survey of its members, finding that one in five heads had had a sabbatical, normally lasting a term.

This had boosted staying-on rates, which were better in the private than the maintained sector, the organisation said.

Mr Lucas said giving state school heads the chance "to do something else" would raise morale.

Deputy heads could also "act up" for a period, helping their professional development.

You need incentives to keep people longer in post John Dunford ASCL general-secretary

Mr Lucas said: "It's not unusual for someone to become a head teacher at the age of 35.

"If that person stays in the job, with all its stresses and strains, for 30 years without a break, that's pretty daunting."

Mr Lucas added: "The range of options for sabbaticals is very broad. Maybe it could involve foreign travel or learning something new.

"I know cost would be an issue and that, if a scheme was set up in state schools, there would need to be rules.

"But the cost of people leaving the profession early through stress would be reduced by having sabbaticals."

The Association of School and College Leaders is calling for all heads who have worked in the same school for five years to get a sabbatical.

'Strategic thinking'

Its general-secretary, John Dunford, said: "It's about sustainability. You need incentives to keep people longer in post.

"It's also important for people to take some time out to think strategically, in a way you don't often get during the course of work."

Mr Dunford said the average age of head teachers was likely to fall because so many of those in post were taking early retirement.

A Department for Education and Skills spokesman said: "No government has done more to support heads because we recognise the challenges the job brings.

"We are supporting heads with record pay, reducing the bureaucratic burden on schools and key reforms to help them manage workloads better.

"The decision to offer sabbaticals are best made by individual schools."