Figures for 2002 show around 3,450 teachers who moved jobs after school closures or local authority re-organisations benefit from locally agreed salary "safe-guarding" arrangements, which are not time-limited.
In September, teaching unions, except the National Union of Teachers and the Welsh union UCAC, signed a deal with the Government and employers which agreed the principle that all such arrangements should end in three years.
But, as The TES revealed in May, the NASUWT and Association of Teachers and Lecturers have been negotiating an eleventh-hour reversal.
A senior official from one of the unions said they were concerned about the ammunition it would provide to the rival NUT, which had been telling teachers they could lose pay because of the deal. Now all future safeguarding deals will be limited to three years by the school teachers pay and conditions document, though existing arrangements are to be protected.
Peter Hudman is one of those likely to benefit. He has had two management allowance points, worth pound;3,312, protected since 1993 when his job as a secondary science specialist on Bradford Council's supply teaching team was cut.
Now based at a secondary in the city, but on secondment as an NASUWT health and safety officer, he said: "I have a great sense of relief. Recent teacher pay rises have not been keeping pace with the cost of living and I couldn't cope with a further cut."
However, David Hart, general secretary of the National Association of Head Teachers, said: "The idea of still receiving a safeguarded salary as result of a reorganisation that took place in 1985, for example, would be seen as amazing by any other employer."
In a letter to Ruth Kelly, the Education Secretary, he said safeguarded salaries would cause budget problems.
Chris Keates, the NASUWT general secretary, has denied a U-turn, saying it was always understood that the issue would be subject to further talks.