Headteachers angered by the erosion of pay differentials are pressing for reform of the system used to assess their salaries.
Following hundreds of complaints from their members, the Secondary Heads' Association and the National Association of Head Teachers are to ask the School Teachers' Review Body to allow governors more flexibility in assessing performance salary awards.
Since 2000, governing bodies have only been allowed to reward the good performance of heads with a salary increase of one point per year on the leadership group pay spine.
The same system will be introduced for deputies in September 2001. This means that differences in pay between heads and deputies and classroom teachers at the top of the scale will shrink still more; differentials have already been eroded by the introduction of threshold payments.
"The differential between the pay of a deputy head and a classroom teacher could be as little as pound;6 a year, which doesn't reflect the substantial extra responsibilities of someone with a management role," insists Magnus Gorham, head of salaries at the NAHT.
"There is a lot of anger among headteachers over the issue, especially as tight school budgets are no longer always the issue when it comes to awarding pay rises based on targets," according to Mr Gorham.
Heads have sometimes forgone these rises for years to save their schools money, only to find that increases are now limited to one point per year. Mr Gorham says that governing bodies often want to reward heads for excellent performance, but their hands are tied.
The NAHT has warned the Department for Education and Skills that the restrictions on pay will have a damaging effect on the retention of headteachers; governors recruiting a new head are allowed a lot more leeway on the salary they offer than those determining the salary of a current head.
The NAHT predicts that heads could well be tempted by better offers from the school down the road. "It is a ridiculous system when the best way for headteachers to get a decent salary is to resign and reapply for their own jobs," says Bob Carstairs, of SHA.
Both unions argue that governors should have more scope to reward heads for an increase in responsibility, like a rise in pupil numbers.
The NAHT believes that the introduction of onerous duties such as performance management and threshold assessment alone should be enough to justify raising the levels of the Individual School Range - the pay band for heads, deputies and assistant heads.
Dr Chris Nicholls, who is head of Moulsham high school, Chelmsford, and the salaries and conditions of service officer for the SHA, believes that the STRB will have to look at various ways of paying heads more.
"The new recruitment and retention allowance will allow heads to award up to pound;5,000 to a classroom teacher they want to keep, but governors can't pay a penny if they want to retain a head. It's an anomaly which the STRB must address," he says.
And while governors are allowed to reassess the salary range for deputy and assistant heads if their jobs become more demanding, a head's range is cast in stone.
Mr Carstairs reckons that 20 per cent of heads are on the wrong point of the professional spine because of faulty assessments by governing bodies.
"The system is so incredibly complicated that only about six people in the country, who actually work in union salary departments, understand it," Mr Carstairs says.
Dr Nicholls also predicts problems in funding performance pay rises in the future. While the Government funded 60 per cent of the performance salary increases awarded in 2000, this proportion has shrunk to 40 per cent in 2001, and Dr Nicholls thinks it could dwindle still further.