The majority of public services “will not be operating” during a widespread strike of teachers, educational support staff and council workers next month, unions have warned.

Teacher unions are warning parents to expect even more school closures on July 10 than early this year as support staff join teachers on strike.

As well as the National Union of Teachers, Unison have also announced their members will be striking with GMB and Unite members also expected to join the action once their ballots Senior union leaders are warning that the July 10 action could even surpass the General Strike of 1926 when 1.7 million workers downed tools.

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 in the coming week.

The public services union said that 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% since the coalition came to power.

The Public and Commercial Services union is also balloting its members for a strike in a long-running dispute over cuts in the civil service, with the result also due by the end of the month, while thousands of midwives and maternity support staff are currently being consulted on whether they want a formal ballot for action..

Phil Clarke, East Sussex rep of the NUT, said the strike was likely to surpass the strike on March 26 this year which affected tens of thousands of pupils across the whole county.

He said: “In terms of the NUT it will be the same broadly speaking as the last strike but with Unison and GMB also likely to be out, it will probably result in a higher level of school closures because of the support staff as well.

“Last time in Brighton and Hove schools were shut across the board last time anyway but in East Sussex it was not quite as high but there was still a very significant level of closures.

“We are still be expected to work until 68 with an ever increasing workload.

“The pay situation is even worse for teachers than support staff because schools don’t even have to pass on the 1% pay rise to teachers, it’s at their discretion.

“With inflation, teachers have been suffering pay cuts for years.

“A key section of the public sector will not be operating on July 10, in fact the majority of the public sector will not be working.”

A Local Government Association spokesman said: "It is disappointing that Unison will be proceeding with strike action.

“Local government staff have worked wonders while councils have been tackling the biggest funding cuts in living memory and we have no doubt that many will still be at work on the day of strike action.”