The National Association of Head Teachers warned of a "brain drain" of heads from schools, as new statistics revealed the scale of the recruitment difficulties facing governing bodies.
An analysis by the association revealed that the number of headship vacancies advertised in The TES has soared to its highest level in six years, with the exception of a "blip" year in 1997.
That was when hundreds of heads left schools in anticipation of a tightening of Government
David Hart, NAHT general secretary, said the exodus reflected the fact that ministerial pledges to reduce bureaucracy and increase budgets had not yet had an impact in classrooms. And salaries were poor compared with similar jobs in the public sector or in industry.
He said: "Government promised pressure and support for schools in equal measure. Until (tha) commitment has been translated into actual delivery, heads will continue to leave and senior staff will decide that the job of being a head is 'not worth the candle'."
A total of 1,799 posts were advertised in The TES in the six months to June 30 - a 50 per cent increase on 1998. The NAHT wants average pay of primary heads to rise to pound;38,000. In the secondary sector, the figure should be pound;54,000.
Kerry George, the association's assistant secretary, said that that she had been told of:
a head who had recently retired being asked to come back to the school and run it on a part-time basis, three days a week;
another head being asked not only to take over the running of a second school, but also to judge its threshold applications; and
another leaving his large comprehensive to become a postman.
A Government spokesman said half of this year's increase in vacancies had resulted from a scheme the NAHT had helped develop to allow heads to retire early.