All state schools in England could be closed by “unprecedented” coordinated strikes involving all four teaching unions, after their leaders vowed to increase pressure on the government to improve its pay offer. In a joint press conference, the leaders of the four major education unions said they wanted to send a message to the education secretary that she needed to resume negotiations over pay and school funding. “The significance of four union general secretaries being aligned in this way should not be understated. It’s a real demonstration of unity on our part and determination on the part of our members, after weeks, if not months, of stonewalling from the secretary of state [Gillian Keegan],” said Patrick Roach, general secretary of the NASUWT. Roach said Keegan had “gone to ground” and was refusing to meet unions. “Her haste to strike a deal has seriously backfired and we’re here today because it has galvanised not just us but our members, rank and file classroom teachers and school leaders who are now going to be balloted for industrial action.” Geoff Barton, general secretary of the Association of School and College Leaders, said the government was “in a parallel universe”, describing the previous pay talks as “bizarre and surreal”. “The nation’s parents are watching on and saying, why is the government not sorting this out? This is a government that wants education on the cheap. They don’t want to pay teachers,” Barton said. If the ballots held by the four unions, including the National Education Union and the National Association of Head Teachers, pass the legal threshold, then the leaders said they would coordinate action in the autumn term this year. Kevin Courtney, joint general secretary of the NEU, said: “I think with our four unions you would find that every state school in England would be affected by the dispute, and that would put it up to 300-400,000 teachers who would be involved in taking action.” In March, the government offered teachers a £1,000 one-off payment alongside an average 4.5% pay rise next year after talks. But members of the four unions rejected the pay offer by substantial margins. On Friday, the National Association of Head Teachers announced that it would again ballot members for strike action. The union held a vote last year but narrowly failed to surpass the 50% participation rate required by law, with union officials blaming the postal strike for members being unable to receive ballots. “We’ve been on this cliff-edge for too long, and enough is enough,” Paul Whiteman, the NAHT’s general secretary, said at its conference on Friday as delegates voted to endorse a ballot. “When it comes to school funding, the government has attempted to fob off the general public with massaged figures and deceptive statistics, but it doesn’t matter if you’ve been made to study maths until the age of 18 or the age of 180, its sums just don’t add up.” The NEU gave notice that it would open balloting from Monday for renewed authorisation to hold strikes until the end of the year. So far the NEU has held five days of national and regional strikes in England, with a further national strike planned for Tuesday. Dr Mary Bousted, the NEU’s joint general secretary, accused Keegan of “washing her hands” over the teachers’ pay dispute by refusing to reopen talks. “The secretary of state, who remains by some distance the biggest obstacle to getting a sensible resolution, needs to address this issue head on and come to the negotiating table with all the education unions. This wilful lack of engagement will be something that parents and teachers will not forget,” Bousted said. Keegan has refused to reopen talks, saying she will wait until she receives recommendations from the independent school teachers’ review body for the 2023-24 pay award later this summer.