Hundreds of thousands of public sector workers will take part in a national strike on June 30, two teaching unions have confirmed.
Millions of pupils at thousands of schools across England and Wales are expected to be affected as members of the National Union of Teachers (NUT) and the Association of Teachers and Lecturers (ATL) stage a walkout in their bitter row over pensions.
The announcement comes ahead of an expected decision by the Public and Commercial Services union (PCS), due later this afternoon, that up to 250,000 of its civil service members will also strike on the same day.
The confirmation of the strike date, which was widely expected to be June 30, comes the day after the two teaching unions announced that their members had overwhelmingly backed a national strike.
More than 300,000 teachers were balloted in total, and the walkout is likely to be the biggest day of action by teachers in decades.
ATL has never taken national strike action in its 127-year history, and the last time it took national industrial action was in 1979, before current legislation on balloting, over changes to teachers' pay.
Cabinet Office minister Francis Maude said it would be a "big mistake" for teachers and civil servants to go on strike while negotiations are going on and the Department for Education has said a strike "will only damage pupils' learning and inconvenience their busy working parents".
The teaching unions say the Government's proposed pension changes will see them work longer, pay in more and receive less when they retire.
ATL president Andy Brown said: "It is with deep reluctance that I announce the date for ATL's first ever national strike - Thursday June 30. We have carefully picked this date to avoid external exams and important school and college events so that any strike causes as little disruption as possible to children's education. We do not want to strike, but unless we take a stand now, the Government will irreparably damage education in this country and children will lose out."
NUT general secretary Christine Blower said: "Teachers do not take strike action lightly but the overwhelming support for action by NUT members shows that teachers feel what is happening to their pensions is wrong. The NUT will continue to take part in the TUC-led negotiations with Government on pensions. So far there is no evidence that the Government is taking those talks seriously. We hope that our action and that of the ATL will persuade the Government to change its attitude."