THE independent review body which advises ministers on teachers' pay is under pressure to lift restrictions preventing governors from giving big rises to headteachers.
The School Teachers' Review Body is due to deliver its report within weeks, as escalating national shortages of senior staff in schools are being reported.
Research to be published next week will show that in inner London two out of every three headships had to be readvertised in the school year 1999-2000.
In the South-east, the number of headships that were readvertised jumped from 24 to 39 per cent, the report by Education Data Surveys will reveal.
Concern about shortages coincides with fears among heads and deputies that their pay differentials are being eroded as classroom teachers begin to pass the performance threshold and receive substantial rises.
A teacher who passes will qualify for a pound;2,000 salary rise and a place on a performance-related pay scale of up to pound;30,000. The leadership spine ranges from pound;28,446 to pound;75,972.
Governors are limited to awarding just one performance point in salary increases to headteachers under pay and conditions rules agreed by ministers in 1999.
The pay system for teachers, meanwhile, includes four management allowances which have replaced responsibility points and three new recruitment and retention allowances.
A teaher who passes the pay threshold will earn at least pound;25,959 this year (pound;28,275 in inner London). With the management allowance that replaced one of the old responsibility points, they could be earning pound;27,444 and an extra pound;909 if their post is difficult to fill or a shortage subject. A teacher with a further management allowance and second retention allowance could earn pound;30, 741.
The two headteacher unions, the National Governors Council and Oxfordshire County Council have now urged the review body to lift the restriction on heads' pay.
David Hart, general secretary of the National Association of Head Teachers, said: "Many governing bodies think it intensely annoying they cannot reward their heads and deputies the way that they want.
"They can't understand why they can reward teachers with pound;2,000 for going through the threshold but when it comes to rewarding their own heads and deputies they are bound hand and foot."
Chris Gale, chair of the National Governors Council, added: "It is extremely unfair. There are no real incentives for headteachers."
The limit was imposed in 1999 when complex changes were made to heads' pay and a leadership spine introduced.
Oxfordshire took the unusual step of submitting its own request for change to the review body. Evidence from local authorities is more commonly presented by the teachers' employers organisation.
The review body's report will be submitted to the Government later this month.