Members of the National Union of Teachers will vote on whether to strike at their annual conference, which will run until tomorrow, if a pay package is set at the proposed 2.45 per cent rise.

The motion put forward by the NUT states a seven per cent pay rise would amount to a "catch-up" to bring salaries in line with other professions.

NUT secretary for Northamptonshire, Gordon White, said he had written to all members in the county to encourage them to back strike action.

He said: "I fully support industrial action. There are a range of grievances against this Government, who just don't listen to us.

"Teaching is a profession where we have no negotiation powers, and a strike would display the unhappiness teachers feel at a below inflation rise.

"The consensus at the moment within the union is that a rise which is below-inflation will not be acceptable.

"This would be the first strike in the profession for 21 years, so clearly there will be members who have never been asked to consider industrial action before and that means there is an unknown element in the ballot.

"But there is a very strong feeling that a strike is likely. It would involve a one-day walk out, on Thursday, April 24."

Other teaching unions have stopped short of calling for industrial action in response to the proposed 2.45 per cent rise, which would be followed by further rises of 2.3 per cent in 2009 and 2010.

Mr White added: "I personally have written to members in the county asking them to vote to strike.

"It is time teachers were rewarded for the work they do and a below-inflation rise does not reflect that."

A spokesman for the Department for Children, Schools and Families said: "Strike action can only achieve one thing . . . disruption to children's learning."