Discretionary awards granted by governors to heads who had met targets and a pay deal weighted towards them were the main reasons for the inflation-busting rises.

The National Union of Teachers said the findings, published by the School Teachers’ Review Body, showed the need for a large across-the-board increase this year. Doug McAvoy, the NUT’s general secretary, said: “We don’t begrudge headteachers their rise - they are under the most enormous pressure. But so are classroom teachers. This just highlights the need for a significant increase for all teachers.”

The union is calling for all teachers to be given a rise of 10 per cent or pound;2,000, whichever is the greater. But Education Secretary David Blunkett has warned the review body hat some authorities will find it difficult to pay for anything much above inflation.

For 68 per cent of class teachers, promotion offers the only hope of a rise beyond the annual round. Ministers have gambled that many will therefore find their new pay structure attractive, as it allows teachers to move to a new scale linked to annual appraisal.

The discretionary rises for heads were used more widely than recruitment bonuses for teachers - only 2 per cent were given the minimum half-a-point despite re-cruitment problems in London and in special schools highlighted in a second review body report.

David Hart, general secretary of the National Association of Head Teachers, said governors had made only limited use of discretionary awards because they did not have the money. “Most heads did not gain anything from discretionary powers,” he said.