Headteachers' leaders have attacked government plans to give more than half the schools in England the right to set teachers' pay and conditions.
Both headteachers' associations predict that most schools will stick with existing national arrangements, which already give them some flexibility on teachers' pay.
"To go down a totally different route means you've got to enter into negotiations with the unions representing your staff, and that can be fraught with difficulty. Most heads would think they have got better things to do," said David Hart, general secretary of the National Association of Head Teachers.
The only possible reason he could see for heads wanting to opt out was if they disagreed with aspects of the existing structure, such as performance-related pay. But if they dropped that, they would have to find another way of rewarding teachers as well or better than they are at present. With most schools already spending more than 80 per cent of their budgets on staffing, that would be difficult.
The plans to allow successful schools to opt out of national pay scales are included in the education Bill now going though Parliament, which also proposes to give these schools the widely welcomed freedom to vary the curriculum.
Originally the Government planned to grant these freedoms only to the most successful 10 per cent of schools. But pressure from opposition parties, who threatened to defeat the Bill in its report stage in the House of Lords, led ministers to hold out the prospect of "earned autonomy" to a larger proportion. Well-led schools with good inspection reports will now qualify, even if their results are poor.
Announcing this concession, education minister Baroness Ashton recently said that 60 per cent of primaries and 30 per cent of secondaries would be able to opt out of national arrangements from next year.
John Dunford, general secretary of the Secondary Heads Association, warned that if some schools did make their pay more attractive, that would change the recruitment equation in their areas and create problems for other schools.
Describing the freedom to vary pay as the wrong kind to offer heads, Mr Dunford said: "We strongly support the principle of autonomy, but autonomy for one school should not be at the expense of others."
Heads could find that scrapping national pay scales actually makes it harder for them to recruit staff, according to Bev Curtis, director of the education personnel consultancy EPM and co-author of a book on teachers'
Mr Curtis does not believe teachers will be keen to apply to schools which pay extra one year but cannot guarantee to do the same in subsequent years.
Past experience suggests that these problems are likely to remain largely academic. Only four grant-maintained schools took advantage of legislation introduced by the Conservatives allowing them to vary teachers'
pay and conditions. When Labour gave schools in education action zones a similar option, they also failed to take it up.
Asked why the Government is set on giving heads powers that they do not appear to want, a spokesman for the Department for Education and Skills said the proposals were intended to enable schools to develop innovative approaches.
They do not have to take up the freedoms," he added.