Probation officers, bus drivers, police civilians and museum staff were among the latest workers to back a pensions strike today, increasing the prospect of the biggest day of industrial unrest for decades.
Unite and the National Association of Probation Officers (Napo) said their members had voted in favour of taking industrial action in protest at the Government's controversial pension reforms.
More than two million workers are now set to walk out on November 30 for a day of action co-ordinated by the TUC, which will disrupt schools, courts, government offices, jobcentres, driving tests, council services and hospitals.
Unite said 75% of those who took part in its ballot said yes to taking part in the strike, with a 31% turnout covering more than 200 employers.
Unite workers at Mersey Tunnels, Greater Manchester Transport, Glasgow City Council, Scottish Water, West Midlands Police Authority, Northern Ireland bus services, Cardiff buses, the British Film Institute, the British Museum and South Yorkshire Police were among those backing strikes.
The union said its vote should heap further pressure on the Government to rethink its plans to "force" public-sector workers to pay more and work longer, but for a poorer pension in retirement.
General secretary Len McCluskey said: "Yet again public-sector workers are telling the Government that enough is enough.
"They have endured wages cuts, rising living costs and horrific job losses, as this Government forces the less well-off in this country to pay for the sins of the elite. They are not prepared to stomach this attack on their pensions too."
Napo said its members voted by a "massive" 83% in favour of industrial action on a 45% turnout. It will only be the third time in its 100-year history that Napo members will take national strike action.
Jonathan Ledger, Napo's general secretary, said: "Napo's members have sent the Government a clear message.
"Its attack on their pension entitlement is not fair, not reasonable and not necessary. They have joined the hundreds of thousands of hard-working public-sector workers who are uniting in defence of their pensions, pensions earned after years of demanding work on behalf of our communities.
"This union does not take strike action lightly. Our members care passionately about their work and remain committed to the best interests of the people whom they serve diligently every day.
"But they also believe in respect and fairness, and this Government is showing them none at a time when cuts and privatisation are creating uncertainty about the future.
"Their pensions are vital to our members, hard-earned and essential for a secure and dignified retirement.
"The Government needs to return to the negotiating table and make real and creditable changes to its pension proposals if this dispute is to be resolved."
Labour leader Ed Miliband urged both sides in the dispute to negotiate.
He said: "There is a huge responsibility on both sides, even at this late stage, to stop the strike happening.
"The unions need to show that they are willing to negotiate, the Government needs to show that it too is willing to negotiate."
Answering questions after a keynote speech on the economy in central London, he said the Government had not moved on the "crucial issue" of the 3% rise in contributions for public-sector workers and had "neither provided an adequate explanation nor do they seem to be doing proper negotiations".
The November 30 walkout is set to be the biggest day of industrial unrest since the 1979 Winter of Discontent.
Cabinet Office minister Francis Maude said: "We have listened to the concerns of public sector workers about their pensions and responded with a new generous settlement which is beyond the dreams of most private employees. I urge the trade unions to devote their energy to reaching agreement and not to unnecessary and damaging strike action, which is often on the basis of low turnout. In Unite's ballot, announced today, less than a third of their members actually voted.
"These new generous protections represent a very big move. They include a more generous 'accrual rate' and protections for anyone within 10 years of their pension age. The settlement will see public service workers getting a guaranteed benefit in retirement, not subject to market fluctuations or fees - something which has all but been eliminated elsewhere.
"It is now time for the unions to respond in a responsible manner. The new deal is conditional on agreement being reached in scheme by scheme talks with the unions."