Millions of public sector workers are preparing for the fight of their lives to defend jobs, pensions and services, raising the prospect of "sustained" strikes, a union leader says.
Dave Prentis, general secretary of Unison, warned of a campaign of industrial action "without precedent", involving more than a million workers which he predicted would "weaken" the Government.
He launched a savage attack on the coalition, saying public sector workers had been subjected to "shabby treatment" at the hands of the "wretched" government.
Mr Prentis also accused Labour of "building a bridge" the Tories were now marching over, adding that Unison should only support Labour candidates who backed the union.
He described his keynote speech to Unison's annual conference in Manchester as a "call to arms", urging the 2,000 delegates to prepare for action when they returned to their region.
"The fight of our lives may be an overused cliche, but this is what this is. A fight we can win, must win - and will win."
He called on ministers to stop "demonising" hardworking people, who he said had had enough of being "bullied", adding that the Government's controversial pension reforms were "daylight robbery".
Public sector workers were being told to pay more into their pension scheme, receive less on retirement, while women only found out on the radio that their pension age is to increase to 67, which "added insult to injury".
Unison will stand behind the teachers and civil servants going on strike on June 30, pledged Mr Prentis, adding: "If the government fails to listen, to heed our warnings, to negotiate in good faith, I say to David Cameron - you ain't seen nothing yet. We will strike to defend our pensions."
Unison's preparations for industrial action were well advanced, said Mr Prentis, pledging that political and public campaigns will be intensified.