Doug McAvoy, general secretary of the National Union of Teachers, said the first one-day stoppage may be timed to disrupt national tests of 11-year-olds in May unless ministers drop their proposals to link classroom salaries to appraisal of teachers' performance.
That could be followed by escalating industrial action, culminating in an extended campaign of disruption if David Blunkett, the Education Secretary, implements the full pay reform programme scheduled for September 2000.
'My strategy is to get the Secretary of State to back off from the daft proposals in his green paper', said Mr McAvoy at the union's annual conference in Brighton. If the Government doesn't give us a reason not to have a strike, we are committed to having one.'
Last year Mr Blunkett won a Treasury commitment to spend A1 billion over the next two years on additional pay increases. But Gordon Brown, the Chancellor, said release of the money depended on a 'something for something' deal with the teachers to produce incentives for better performance.
Substantial pay rises above inflation were to be directed mainly towards experienced teachers who passed a performance review in September 2000. They would then be entitled to a bonus of about £2,000 and set on a new salary scale that would reward superior classroom performance and managerial responsibilities.
Ministers have warned that the Treasury would claw back this money if Mr Blunkett could not deliver the link between pay and performance.
Mr McAvoy said Mr Blunkett could no longer tell the Teachers' Pay Review Body that a decent pay settlement was unaffordable. 'Of course they will be forced to release the £1 billion. There is no magic date on which it disappears,' he said.
Mr Blunkett was heckled when he addressed the conference on Saturday. He asked delegates to join him in celebration of the Government policies with which they agreed such as smaller class sizes and renovation of crumbling schools. But his list of New Labour achievements was answered by cries of 'worse than the Tories'.
Mr McAvoy told the hecklers that their intervention was 'perverse'. He said the union should be criticising the Government over what it was doing wrong, not over what it was doing right.
But Mr McAvoy supported conference resolutions for industrial action. The first, passed on Saturday, called for a boycott of the Government's plans for teacher appraisal and a one-day national strike in the summer term 'unless the proposals to link appraisal and pay are definitively withdrawn'.
The second, passed yesterday, called for a more general programme of strikes against the 'ill-conceived, misguided, divisive and bureaucratic' proposals in the green paper.
A third resolution demanding a 10 per cent pay increase plus £1,000 was being debated yesterday. Mr McAvoy's supporters on the executive backed an amendment to make the demand less specific, but they agreed that strike action may also be necessary over pay. Votes on this point may not be completed until tomorrow.
Mr McAvoy acknowledged that it may not be reasonable to expect teachers to boycott a performance review that might qualify them for £2,000 pay increases in September 2000. 'The union would look for more disruptive and more hostile action after September 2000 if the Government sought to impose its proposals,' he said.
During the debate Fran Postlewaite, a Barnsley teacher, said: 'It's not a new pay structure we want, it's more money. The rich have had 20 years at our expense. Now it's our turn.'
Jane Nellist, a Coventry teacher, said the Government's plans would damage children by putting them under pressure to achieve good test scores to boost teachers' earnings.
'Play will disappear altogether...Children will be taught about commas instead of being allowed to play in the sand tray.'
Estelle Morris, the school standards minister, is expected to announce concessions when she addresses the National Association of Schoolmasters/Union of Women Teachers conference in Eastbourne tomorrow. They are likely to include a delay in the timetable for teacher appraisal.
But Mr McAvoy said his union would not be 'conned' by minor adjustments and would take industrial action if the Government did not abandon its plans for performance incentives.'You can't fudge the National Union of Teachers. Our position is clear. We will not accept the link between appraisal and pay,' he said.
: Actor Tony Robinson, who played Baldrick in TV's Blackadder, has backed claims by Chris Woodhead's former wife Cathy that the chief inspector's affair with Amanda Johnston began while she was a pupil and he a teacher at Gordano school in Bristol something he and Ms Johnston have consistently denied. Mr Woodhead said yesterday he had 'absolutely no comment' on the actor's claims.
Reports on Saturday suggested that notes written by Mrs Woodhead's then lawyer during the course of her divorce in 1976 back her claims that her husband had committed adultery with Amanda Johnston on 'several occasions'.
