Council and school support staff are to strike on July 10 after voting in favour of industrial action over pay.
Unison said its members in England, Wales and Northern Ireland will walk out for 24 hours, with other unions set to announce a similar move.
Unison announced that its local government members backed action by 58 per cent in protest at a pay offer worth one per cent for most workers.
Unison general secretary Dave Prentis, said: “Many of our members are low paid women earning barely above the minimum wage, who care for our children, our elderly and our vulnerable and they deserve better treatment than they have had at the hands of this government.”
Unison said local government workers have been “condemned” to three consecutive years of pay freezes, followed by below-inflation rises in 2013 and 2014, leaving their pay reduced by almost 20 per cent since the coalition came to power.
The GMB and Unite will announce voting results over the next week, while the Public and Commercial Services union is balloting its members for a strike over cuts in the civil service,.
Mr Prentis has predicted that a walkout on July 10 could be bigger than the General Strike.
Members of the National Union of Teachers will also take industrial action on July 10, while firefighters in England and Wales have staged a series of walkouts over pensions and have not ruled out further stoppages.
Meanwhile, midwives in England could soon be balloted for industrial action in protest at the Government’s controversial decision not to accept a recommended one per cent across the board pay rise for NHS staff.