Sixth-form college teachers are being consulted on staging strike action in protest against a proposed pay rise of 0.75 per cent.
The rise, which is less than a third of the increase given to their school counterparts, has been branded "unsatisfactory" by teaching unions.
The NUT, NASUWT and ATL are consulting their members on whether to accept the offer tabled by the Sixth Form Colleges' Forum (SFCF), which would be backdated to September 2010.
The offer is higher than the 0.2 per cent offered to further education lecturers, while the massive cuts set out in the comprehensive spending review had led to fears there would be no increase.
Christine Blower, NUT general secretary, wrote to members, advising them to reject the offer in a consultative ballot, and encouraged them to support strike action if no deal can be struck.
With the retail price index (RPI) measuring inflation for September 2010 at 4.6 per cent, the union warned that the small rise - worth an extra #163;225 on a salary of #163;30,000 - would amount to a real-terms pay cut of 3.85 per cent.
The offer is also significantly smaller than the 2.3 per cent increase awarded to state-school teachers in the current academic year, meaning there is no pay comparability between sixth-form and schoolteachers for the first time since 2003.
In her letter to members, Ms Blower wrote: "The NUT national executive believes... that the pay offer is unsatisfactory and should not be accepted at this stage.
"The NUT is therefore recommending that you vote to reject the offer. The NUT is also consulting you about whether you are prepared to take strike action if necessary."
Following lengthy negotiations with the unions, the SFCF's formal pay offer also includes a long-term undertaking to bring pay in line with schoolteachers, as well as a commitment to hold further meetings on pay and funding issues.
A spokesman for the NASUWT, which is also consulting its members, said: "This is undoubtedly the first step on the slippery slope to a major pay disparity. The NASUWT is very unhappy with the offer and sees no justification for it being so low."