The prospect of months of industrial unrest has grown as the leader of one of the country's biggest unions warned that more than a million public sector workers were set to take strike action in the autumn unless the Government pulls back from its controversial pension changes.
Dave Prentis, general secretary of Unison, said huge numbers of local government workers and NHS staff were "on the road" to industrial action, highlighting a "perfect storm" of pay freezes and lower pensions.
His warning came ahead of an announcement on Tuesday by the Association of Teachers and Lecturers (ATL) and the National Union of Teachers (NUT) of ballot results for industrial action over moves which they say will see teachers working longer, paying more and receiving less when they retire.
The two unions are balloting almost 300,000 members. The ATL has never taken national strike action before.
The Public and Commercial Services union will announce the result of its strike ballot on Wednesday, raising the prospect of up to 750,000 teachers, civil servants and other public sector staff going on strike on June 30.
Mr Prentis said balloting of around 1.2 million Unison members will start soon unless a crunch meeting with the Government on June 27 leads to a deal.
He warned that the Government was on a "collision course" with public sector unions over pensions as well as cuts to jobs, pay and services, adding: "If we are prevented from reaching agreement we will move to a ballot in the summer or early autumn. It will not be one day of action - it will be long-term industrial action throughout all our public services to prevent destruction of our pension schemes.
"I have no doubt that unless the Government pulls back from its attempt to decimate public sector pensions, this union will move to industrial action."
Mr Prentis said planned changes to pensions would lead to public sector workers paying in more, receiving less in retirement and working longer.
He warned of "massive industrial unrest" later in the year, adding; "It is very clear we are on a collision course unless the Government changes its policies."