All the main unions representing teachers in England have come out against the changes the government wants to make to the way they are paid.

These are the main features of the new system, as set out in the government's consultation document, Teachers: Meeting the Challenge of Change:

New appraisals

The government says there would be "a thorough annual assessment of teachers' performance against agreed objectives". Whether this can be objective and fair, especially if linked to pupils' results, is hotly disputed by the unions.

The idea is that the appraisal should have a bearing on whether teachers would get annual pay increments.

Pay scale

As now this would award classroom teachers points for experience and taking on additional responsibilities. There is currently a nine point maximum, which gives teachers about £23,000 a year.

The government wants to introduce a new "performance threshold" above that. The government says teachers whose performance was judged to be satisfactory on appraisal could expect to receive annual increments up to the threshold.

Those who fell below expectations might not gain an increment each year, "excellent performers" might get two.

Extra responsibility

Teachers who take on extra responsibility - such as special needs teaching or subject co-ordinator - may receive salary supplements, the amount being at the discretion of the headteachers and governors.

Supplements can also be paid to recruit and retain staff.

Above and beyond

Once on the nine points, teachers would have a right to apply for assessment to cross the threshold and get increased pay.

The government says crossing the threshold would be an important career step, with success depending on "high and sustained levels of competence, achievement and commitment".

Appraisal arrangements would combine internal and external assessment against new national standards with strong classroom performance at their core.

Suspicions

Teachers above the threshold would have higher pay ranges - up to £35,000 a year. The idea was to have been that this would reward good teachers for staying in the classroom, whereas at present they have to move into management to get higher salaries.

But they would be expected to be "extending pupils' learning opportunities and devoting more of their own commitment and time to their own professional development".

A teacher's individual pay range at this level would depend on performance and responsibility, with any further pay steps based on a review of their performance.

The unions say that such individual contracts would mean abandoning collectively-agreed hours, although they complain that many teachers already do far more than they are contractually obliged to do.

And there is another problem: it does not matter what a school thinks its teachers are worth if it does not have the money in its budget to pay them.

Different elsewhere

Technically, these proposals apply only to England, which is all that the Department for Education and Employment, under David Blunkett, is responsible for. A separate consultation document was issued for Wales but the proposals it contains are essentially the same as these.

As with most education matters, there are different arrangements for Scotland and Northern Ireland, where pay is negotiated between the unions and employers - the education authorities or education and library boards - without the filter of an independent review body.

This might change once the Scottish Parliament and Northern Ireland Assembly are up and running.