Doug McAvoy, general secretary of the National Union of Teachers, said that the pay review body proposals, which mean a starting salary of nearly pound;20,000, in inner London, would still leave teaching lagging behind other professions.

He told a London rally that a repeat of the independent Houghton inquiry, some 30 years ago, was needed to stem the loss of teachers and turn around recruitment.

“Houghton set the average salary for teachers 37 per cent above average earnings. Today, salaries are just 4.5 per cent above average,” he said.

“Teachers’ starting salaries are not competitive with other professions, nor do they keep pace with increases in the private sector. London allowances certainly don’t keep pace with the cst of living in the capital.”

An NUT survey, produced by recruitment expert John Howson, suggests nearly 10,000 extra teachers are needed in London alone, to cover vacancies and bring teacher-pupil ratios back to 1987 levels.

Both the NUT and the National Association of Schoolmasters Union of Women Teachers are balloting London members on industrial action over covering vacant posts. Ballots are also expected outside the capital next week in up to six authorities.

But Graham Lane, the Local Government Association’s education chair, said the latest rise in London allowances alone would cost the capital’s boroughs around pound;1m each.

“Authorities will only find this by slashing Standards Fund money, repairs and classroom assistants. Teachers may get a few extra pounds but they will not thank the Government for making their jobs harder.”