Four major teaching unions have announced an “unprecedented” attempt to stage a joint walkout that could see almost every school in England closed.

If members agree, teachers and head teachers would strike together in the autumn, causing mass disruption.

On Friday, union leaders urged teachers to vote for industrial action after rejecting a 4.5 per cent pay offer from the Government.

The general secretaries of the National Association of Head Teachers (NAHT), the Association of School and College Leaders (ASCL), the National Association of Schoolmasters Union of Women Teachers (NASUWT) and the National Education Union (NEU) met in Telford, Shropshire, to synchronise the planned strikes.

They would see hundreds of thousands of teachers strike over what they have described as “unbearable” workloads, “squeezed” school funding and “contemptuous” pay offers.

All state schools, sixth form colleges and even some independent schools would be under threat as a result of the plans. Members will be balloted on the joint action in the summer. 

One union boss said the teaching profession had been united “in its determination to not accept the poor offer currently on the table”.

It comes after all four unions turned down a £1,000 one-off payment from the Government for the current school year. The decision on teachers’ pay in England for next year has now been passed to the independent pay review body, the School Teachers’ Review Body (STRB).

The deal also included reforms to Ofsted that would have given head teachers “greater clarity” on when to expect their next inspection.

It comes after the death of Ruth Perry, a headteacher at Caversham Primary School in Reading, Berkshire, who took her own life in January while awaiting an inspection report that downgraded her school from the highest rating to the lowest possible.

On Thursday, teacher members of the NEU staged fresh strikes in schools and sixth form colleges, with another national walkout planned for Tuesday.

Paul Whiteman, the general secretary of the NAHT, said: “This is an unprecedented show of solidarity from the education unions. It sends a clear signal to the Government that our dispute is not going away. Any illusions they may have had that we would be put off by their derisory first offer and refusal to continue to negotiate should be shattered.

“School staff will not put up with eroded pay, squeezed school funding and unbearable workload and working conditions any longer – and we are fully united together in fighting for change.”

‘Blame will lie squarely at Government’s door’

Kevin Courtney, the joint general secretary of NEU, said: “In washing her hands of any responsibility for resolving the teacher pay and funding dispute, the Education Secretary has united the teaching profession in its determination to not accept the poor offer currently on the table.

“Parents and the education profession will be in no doubt that if further industrial action needs to be taken, the blame for this will lie squarely at the Government’s door.”

Dr Patrick Roach, the NASUWT general secretary, said: “Teachers know they are worth more than the Government has offered and are determined to continue their fight for a better deal.

“The Education Secretary needs to recognise that the way to resolve this dispute it by getting back around the table. The Government must negotiate a deal that is acceptable to our members or deal with the consequences.”

Geoff Barton, the general secretary of ASCL, said: “We have made every effort to resolve this matter through other means. Sadly, the Government’s refusal to reopen negotiations after their offer was comprehensively rejected has left us with no other option than to ballot for strike action.

“It is clear that all unions feel the same way and we are committed to working with them to fight for fairer pay, improved funding, manageable workloads and other changes that are needed to ensure schools have the capacity to provide the level of education that children and young people deserve.”

A Department for Education spokesman said: “Any strike action is hugely damaging. We have made a fair and reasonable pay offer to teachers, recognising their hard work and commitment. Thanks to the further £2 billion we are investing in our schools, next year, school funding will be at its highest level in history.”