Teachers today overwhelmingly backed a national walkout in a row over pensions.
Members of both the National Union of Teachers (NUT) and the Association of Teachers and Lecturers (ATL) voted in favour of strike action, in protest at the changes the Government is planning to make to their pensions.
The unions say the plans will leave teachers working longer, paying more and receiving less when they retire.
A walkout is now set to take place on June 30, affecting millions of children at thousands of schools in England and Wales.
Results from the NUT's ballot show that 92% were in favour of strike action.
Turnout was 40% among state school members of the union and 27% among private school members.
The NUT's executive will meet tomorrow to discuss the results. The final decision on whether the union will stage a walkout rests with the executive.
Some 83% of ATL members voted to strike, and overall turnout for the ballot was 35%.
NUT general secretary Christine Blower said she was "very pleased" with the turnout and the result.
"I think this shows, across the whole of our membership, exactly how angry people are about these pension changes.
"It shows the determination from teachers and across the public sector that pensions really must be protected - they are fair and sustainable."
Ms Blower said it was a requirement for the union's national executive to meet tomorrow, to make a final decision on action, but in the knowledge that "these are good results on the back of a very strong campaign".
She added: "The Government's unnecessary attack on public sector pensions has convinced NUT members that there is no alternative but to support strike action.
"It is disgraceful that the Government is pressing ahead with its reforms which will affect teachers' pensions.
"The Government knows that they are affordable. This is a policy which has nothing to do with economics and everything to do with politics.
"The NUT is party to the TUC negotiations with Government to protect public sector pensions. It is not too late for common sense to prevail and for these unnecessary changes to be stopped.
"It is in no one's interest to create a whole new swathe of people who are a burden on the taxpayer in old age."
It is the first time in ATL's 127-year history that the union has voted for a national walkout.
Some 27,563 ATL members voted (35%) and of those 22,840 voted to strike (83%), and 4,653 voted against.
Among both private and state school members, 83% voted in favour of a national strike.
ATL general secretary Dr Mary Bousted said: "This is a warning shot across the bows to the Government. When even the least militant education union and teachers working in private schools vote to strike the Government would be wrong to ignore it.
"We didn't want to have to ballot members to strike, but the Government gave us no choice because it is planning to announce a large increase in pension contributions within weeks."
This is despite changes made to the Teachers' Pension Scheme in 2007, she said.
"We don't want to have to strike now. What happens next is up to the Government. If it negotiates in good faith we can all avert unnecessary disruption to pupils, schools and colleges across England and Wales.
"But if the Government continues to push ahead with such radical plans to change teachers' and lecturers' pensions it leaves us no choice - we will have to defend members' pensions and there will be a strike. We are willing to negotiate any time and anywhere - is the Government?"
ATL president Andy Brown said: "The Government's plans to fundamentally change our pensions will ultimately damage children's education. It will mean fewer people wanting to train as teachers or lecturers, and make it unaffordable for young teachers saddled with student debt to join the pension scheme. Schools will lose great teachers, lecturers and heads, and it will be incredibly hard for schools to recruit heads, particularly at primary level."
ATL said it will make a final decision on a strike date tomorrow.
Mark Serwotka, general secretary of the Public and Commercial Services union, which will announce the result of its strike ballot tomorrow, said: "These results send a clear message to the Government that public sector workers do not believe they should be made to pay with their pensions for a recession they did not cause, and we send our support and solidarity to all NUT and ATL members.
"All the experts who have looked at public sector pensions, including the Government's own adviser, Lord Hutton, agree they are affordable now and in the future. The Government is isolated in its belief there is a need to cut pensions even further, and the only conclusion to draw is that ideology is replacing reality."
Sally Hunt, general secretary of the University and College Union, said: "Educators do not like taking strike action. Our chosen vocation is to change lives and transform life chances and we are unlikely militants. However, while ordinary people suffer huge cuts in their standards of living, the richest 1,000 people in Britain saw their collective wealth rise by 18% last year."
UCU members in further education colleges and the post-1992 universities, mainly former polytechnics, were balloted for action earlier this year and in March lecturers at nearly 500 colleges and universities across the UK took strike action. They are also expected to join the action at the end of the month.
Russell Hobby, general secretary of the National Association of Head Teachers (NAHT), said: "While our members will not be joining the strike on June 30, the health and safety of pupils will remain paramount. Each head teacher will perform a risk assessment for their school, based on the ratio of adults to pupils. If they can keep the school open safely they will, if not the school will close for the day.
"Closing a school inevitably causes inconvenience for parents, who themselves are struggling with the results of the recession and cutbacks. We can't help but worry about that. But safeguarding the long-term future of our education system is critical. The planned changes to pensions will demoralise the profession, discourage talented recruits and encourage experienced staff to leave. We must make some difficult choices now to prevent that from happening."
The NAHT is due to decide later this week whether to ballot members over strike action.
A spokesman for the Department for Education (DfE) said: "The Government is committed to working openly and constructively with unions to ensure that teachers continue to receive high quality pensions, and that the interests of all professionals are represented fully as pension reform is taken forward.
"Lord Hutton has made it clear that there needs to be a balance between a common framework for all schemes and the need for flexibility to take account of specific workforce circumstances, such as those of the teaching workforce.
"But we are clear that a strike by teachers will only damage pupils' learning and inconvenience their busy working parents. The wellbeing and safety of pupils must remain paramount."
Altogether, ATL and NUT balloted almost 300,000 members, but if joined by other unions, it could mean around 750,000 public sector workers taking part in a walkout on June 30, against not just pension changes but cuts to jobs and pay freezes.
Unison's leader Dave Prentis warned yesterday that over a million public sector workers were "on the road" to taking industrial action in the autumn unless the Government pulled back from its controversial pension changes.