Pay rethink urged on the Government
A clause in the agreement allows for a review if average inflation goes above 3.25 per cent for the whole year.
Pay rises had been fixed at just 2.5 per cent for September 2006 and 2007.
At best, a review could result in a back-dated pay rise for teachers to cover both years.
The Government may give the go-ahead for a review but it is unlikely that it will agree to top up teachers' pay.
The news comes just a week after the NUT and NASUWT threatened national strike action over the Chancellor's threat to restrict future public sector pay rises to 2 per cent from 2008 to 2011. For the average teacher, under current inflation rates, this would amount to a pay cut of more than pound;3,000 by 2011.
Unions are due to submit their evidence to the review body on the future pay deal next month.
Under Labour, the average qualified full-time teacher's salary has risen by 43.7 per cent, from pound;22,790 in 1997 to pound;32,760 in 2005. But there are fears that if pay rises fall out of line with inflation, the sector could face another crisis of recruitment and retention.
Steve Sinnott, the general secretary of the NUT, said teachers had seen "boom and bust" in their pay levels for more than 30 years.
"For some months it has been clear to us that the imposed settlement was inadequate against increasing levels of inflation," he said.
Mary Bousted, the general secretary of the Association of Teachers and Lecturers, said: "We can see the advantage of multi-year pay deals but no one can expect unions to sign up to them if they are not inflation-proof."