UNISON members threw their weight behind the mass co-ordinated strike on July 10 yesterday.

The 600,000 local government workers will walk out alongside members of teachers’ union NUT and may also be joined by members of GMB, Unite and PCS.

Unison general secretary Dave Prentis said the July 10 action could be “bigger than the general strike” after 58 per cent backed a strike in protest at the 1 per cent pay rise offered by employers.

And Unison officials said the year-on-year pay freezes imposed by the Con-Dem coalition since it took power in 2010 have also been suffered by members of other unions.

Up to two million workers could take to the streets next month.

The NUT said last week that it would join the strike after talks with Education Secretary Michael Gove about his attacks on their pay and pensions went nowhere.

And strike ballots at GMB, Unite and PCS will close in the coming days.

“We expect to be joined in that action by other unions in local government and will be campaigning amongst our members for maximum support on that day,” said Mr Prentis.

“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.”

Both the GMB and Unite have urged their members to vote Yes.

Unite assistant general secretary Gail Cartmail said that “it is time to take a stand,” while public-service union PCS has encouraged co-ordinated action between unions.

NUT deputy general secretary Kevin Courtney said joint action will force the government to listen.

“It looks increasingly likely that July 10 will be a day of action across the public sector,” he said.

“It is clear that combining can put extra pressure on ministers to resolve the different disputes.”

The ballot result followed hot on the heels of Saturday’s enormous People’s Assembly Against Austerity march in central London.

“It’s fantastic news that Unison has voted for strike action over pay,” national secretary Sam Fairbairn told the Morning Star.

“But when you look at how hard workers are being hit and how increasingly unpopular this millionaire government is, it’s not surprising that people are willing to take further action.

“This result, and the massive turn out for the People’s Assembly national demonstration on Saturday, gives a good indication that July 10 could become the focus point for anyone wanting to stop austerity as up to two million people could be walking out together in the biggest co-ordinated strikes for years.”