Thousands of civilian workers in the Ministry of Defence and staff in other Government departments are to join another national strike next month in the long-running row over public sector pensions.
The Unite union said around 25,000 of its members, including vehicle maintenance workers, technicians and drivers, will walk out on May 10 alongside civil servants and health workers.
The move follows a 94% vote rejecting the Government's controversial pension reforms, which Unite said would force employees to work longer, pay more and receive less in retirement.
Civil servants in the Public and Commercial Services union, health workers in Unite and members of the Royal Fleet Auxiliary (RFA) are also striking on May 10 in what will be the biggest day of action since last November's stoppage by more than 1.5 million public sector employees.
Unite general secretary Len McCluskey said: "The emphatic rejection of the proposals by our MoD and Government department members makes clear that ministers need to return to the negotiating table for genuine and meaningful talks.
"Unite members in the MoD and the NHS will be joining with other public sector employees in protest against the fact that the Government has continually ridden roughshod over public sector workers.
"The public sector workforce is being systemically targeted by the right-wing coalition to be the whipping boys for the grotesque failings of the financial elite that have brought this country to its knees economically.
"The dogmatic menu served up by George Osborne for the public sector is highly unpalatable - pay freezes set against a backdrop of high inflation, paying more for pensions and large-scale downgrading of staff, with regional pay looming.
"Our members have quite rightly concluded that they have had enough and they will be making a strong showing on May 10 to show their disgust at the way they have been treated."
Members of the Rail, Maritime and Transport (RMT) union employed by the RFA will also take industrial action next month.
General secretary Bob Crow said: "RMT members on the Royal Fleet Auxiliary, the service that supplies the Royal Navy fleet around the world in times of both war and peace, will be standing shoulder to shoulder with hundreds of thousands of other public service workers on May 10.
"We will be sending the clearest message to the Government that we will defend our pensions to the hilt and the demand that our members should work longer, pay more and get less will be thrown back in the faces of this Government of millionaire public schoolboys.
"It's the bankers and the bosses who have gambled with our country's future and the men and women who provide the lifeline services to the Royal Navy fleet should not have to tolerate a worse pension and be forced to work longer to make up for their mistakes."
Unite said it had suspended its industrial action by health workers in Scotland after the Holyrood Government agreed to fresh talks on the NHS pension scheme.
The union, which has 100,000 members in the health service, including 15,000 in Scotland, urged the Westminster Government to follow suit.
Unite's head of health, Rachael Maskell said: "The latest developments in Scotland have dealt a hammer blow to the coalition government's draconian plans to make hard-working NHS employees work till they are 68, pay more for their pensions and get less when they eventually retire."
"We welcome this move and Unite will enter these negotiations in good faith with the goal of obtaining an equitable and fair settlement for NHS staff."