Hardliners in Britain’s biggest teaching union will mount fiery attacks on the Government’s “miserly” pay settlement as to win over 200,000 members for the first national teachers’ strike in 20 years.

The NUT annual conference, which starts today in Manchester, will be dominated by the debate about the below-inflation pay settlement. A national ballot over a one-day strike on April 24 closes at the end of this month.

The Government said its offer was fair in the economic climate, and the proposal to strike would disrupt children’s learning. Pay will rise 2.45 per cent this year, and 2.3 per cent in 2009 and 2010.

A spokeswoman for the Department for Children, Schools and Families said: “Everybody understands that we need to have a firm control of public-sector pay to keep inflation low, mortgage rates low and the economy stable.”

Chris Keates, general secretary of the NASUWT union, said her members were also concerned about pay: “There will be deep anxiety about making sure that the value of teachers’ pay is not eroded over time and emphasis on the need to ensure that the significant gains of the last few years are maintained,” she said.

But a poll by the NASUWT, which begins its annual conference on Monday in Birmingham, showed little interest from its members in walking out.

The Association of Teachers and Lecturers, which ended its conference in Torquay yesterday, will not take industrial action either.

NUT insiders say strike supporters will want members to down tools, however low the turn-out.

Civil servants in the Public and Commercial Services Union and lecturers in the University and College Union are also considering strike action on April 24. But the NUT’s absence from the “social partnership” between unions and government means it is alone in campaigning for industrial action.

The TES has learnt that the NUT executive originally agreed in principle to ballot for a series of one-day strikes, but opted for a more marketable single day of action. If members vote against a strike, it could represent an embarrassing defeat for the executive, which has been lobbying members to support it.

Dave Harvey, executive member for outer London, said he was confident enough to have booked the Central Hall in Westminster for the mass meeting. “We expect thousands to attend the rally,” he said.

Kevin Courtney, Camden branch secretary and member of the national executive for inner London, was also on-message: “We’ve had overwhelming support and I’m confident there will be a strike.”

In 2003, the union stopped short of calling for a boycott of tests for 11-year-olds after only a third of primary members voted for it. At the time, executive member Jerry Glazier said members felt vulnerable taking part without other unions’ support.

This year, there is an increased need for solidarity, with an early Easter meaning the unions’ conferences clash with classes.

Other pay issues at the NUT conference include starting salaries for new teachers and fair pay for agency workers. At the NASUWT congress, teachers will express concern about difficulty obtaining the additional responsibility payments and pay progression to which they should be entitled.

However, the conferences will not be dominated by money. Teachers are very concerned about workload and class sizes. An NUT motion calls for strike action before Christmas if talks with the Government “fail to ensure sufficient progress towards ensuring an acceptable work-life balance”.