Teaching unions are digging in for a fight over which staff should be rewarded for extra responsibilities under a new pay system.
Heads, already warning the end-of-year deadline for reviewing staffing structures will be too tight, say unions are adding to the pressure by demanding that all the estimated 192,000 teachers on management allowances receive new teaching and learning responsibility payments (TLRs).
The introduction of the payments, worth between pound;2,250 and pound;11,000, from January is expected to mean thousands of teachers will lose out because they are awarded for teaching and learning rather than management.
But The TES has seen advice from the three main teachers' unions to heads in Croydon saying all teachers on management allowances worth between pound;1,638 and pound;10,572 should receive the new payments. It says no teacher should take on extra responsibilities without receiving one.
The advice contradicts that issued by the rewards and incentives group (RIG), made up of government, union and employer representatives. It has agreed that there should not be a straightforward transfer between the two systems and that savings from the changeover will help to fund experienced teachers' pay.
David Hart, general secretary of the National Association of Head Teachers, has written to Ruth Kelly, the Education Secretary, to say that officials from the NASUWT, the second-largest teaching union, and the Association of Teachers and Lecturers are openly briefing against deals signed by their leaders.
Andrew Swatland, head of Selsdon primary and Croydon NAHT president, said he would not be swayed by the local advice.
Mr Swatland said: "We will do what is best for our pupils in consultation with our staff. This is going on because the NASUWT and the ATL are sensitive to the National Union of Teachers claiming they have sold their members down the river."
The NUT, which has never been a member of RIG, has issued national advice threatening strikes to prevent its members from losing out.
Mr Hart said NASUWT officials in other authorities had threatened industrial action if members lost out in the staffing reviews. But the union denied the allegation and said its Croydon advice had been withdrawn.
Chris Keates, NASUWT general secretary said: "We expect this sort of thing from the NAHT. It tried the same sort of thing with the workforce agreement and that came to nothing as well."
Mary Bousted, general secretary of the ATL, accused the NAHT of sour grapes because it had pulled out of RIG.
She said her Croydon branch secretary had withdrawn her advice after the ATL's policy had been explained to her.
Mr Hart's letter to Ms Kelly appeals to her to lengthen the staff review timetable. It came as the implementation review unit, the panel of heads appointed by the Government to monitor the policy's impact, said it was making a second request to ministers to assess the workload involved.