Thousands of schools are expected to close on Wednesday as support staff go on strike over proposed changes to their pensions.
It is the latest sign of growing anger in state schools over ministers'
plans to increase the normal retirement age for public-sector workers from 60 to 65.
Pressure on the Government increased after the largest teachers' union, the National Union of Teachers, announced a ballot for its own strike over the issue next month, which could cause chaos in schools across the country.
Next week's strike will also disrupt the Department for Education and Skills with both main civil service unions taking part in the pensions protest.
But it is the action by school support staff that is expected to cause the most disruption. Recent support staff strikes in Brighton and Hove led to more than half of schools closing and others sending pupils with special needs home.
Wednesday's action is expected to affect all 111 English and Welsh authorities that will not yet have broken up for Easter.
Ben Thomas from Unison, the largest support staff union, said: "Our members are very upset. A lot are part-time, low-paid workers, who get poor pensions and this can only make it worse."
School support staff from the GMB and TG unions will also join Wednesday's strike.
Unions were not hopeful that last-minute talks, continuing as The TES went to press, would resolve the situation.
Tony Conway from the Public and Commercial Services Union, which represents nearly three-quarters of DfES officials said the strike could affect the drafting of the Government's long-delayed youth green paper.
He expected the disruption would be magnified because of recent cutbacks in the civil service.
"Members in the DfES are very annoyed," he said. "These changes are being imposed, there has been no discussion."
Wednesday is also likely to see up to 200 senior DfES mandarins striking for the first time since 1981, after First Division Association members voted for action.
National Union of Teachers' members are being balloted after a consultative survey revealed that 70 per cent were prepared to stage a one-day strike over pensions.
Steve Sinnott, general secretary, said: "The Government is not listening to teachers and other public-service workers about the injustice of its proposals. I want members to support a one-day strike."
The Association of Teachers and Lecturers is expected to consider a motion recommending "a ballot of members in contemplation of calling on members to participate in industrial action" over the proposed pensions changes at its conference in Torquay on Wednesday.
The National Association of Schoolmasters Union of Women Teachers is also considering a strike ballot over the pensions issue after an online survey of its members found that 58 per cent supported a strike.
But Chris Keates, NASUWT general secretary, said her executive believed the possibility of constructive talks with Government on the issue had not yet been exhausted.
The Government wants to raise the pension age for all public-sector workers because it fears growing life expectancy will cost taxpayers billions of pounds.