Strikes in schools across England may still happen in September, after local branches of the largest union representing teachers told the Observer this weekend that they would vote against the proposed pay offer. Two weeks ago the government announced that it would accept the recommendation of the independent School Teachers’ Review Body for a 6.5% pay rise for most teachers from September, and the four education unions representing teachers and heads advised their members to vote in favour of the offer. But on social media last week, many teachers and heads were arguing that the rise was not enough to solve the crisis in retaining and recruiting teachers. Many also said they did not trust government reassurances that the deal was properly funded. After emergency meetings last week, some local branches of the National Education Union (NEU), the largest education union – including ones in Oxfordshire, Worcestershire, Birmingham and some parts of London – defied their national executive and recommended that their members reject the offer. Leigh-Amanda Seedhouse, a special educational needs (SEN) teacher and the secretary of the Oxfordshire branch of the NEU, said: “There is anger out there that this offer is still short of what we were asking and most certainly does not redress the real-term losses we have all suffered over the past 13 years.” She told the Observer that one SEN school in her area had already been forced to move to opening only four days a week because of teacher shortages. “We can’t continue with the current crisis and this offer won’t fix it,” she said. One significant issue is whether schools can afford the proposed pay rises. The Department for Education has said 3% will come from “reprioritising” within its own budget, though it said no cash would be taken from “frontline services”, including SEN funding, school building, nurseries or funding for those aged 16 to 19. Schools will be expected to fund the remaining 3.5% from their budgets, drawing on the £2bn which the government said it would provide for each of the next two years in last year’s autumn statement. But some schools say this money has already been taken up by the rising cost of energy and everything else they buy, because inflation has soared. The head of a primary school in Birmingham said she and her staff would be voting against the pay offer because their budget was already at breaking point. “It is an utter fallacy to say this is funded,” she said. “Yes, the government did put in more money, but it was all sucked into the hole that was already there.” She added: “We’ve reached the precipice. My worry is that no amount of money will fix the serious problems we have now after being underfunded for so long.” The head said she could not afford to order even basics such as paper this term. The school had been hiring its own family support worker for one day a week because public services were now so depleted that families had been left with no outside support, she said. However, this term they had had to let the support worker go because they could not afford to pay her. “She was helping families where six people were living in a two-bed flat full of mould and needed help to get out,” the head said. “It is bad enough that we had to hire someone to do this sort of thing ourselves, but now having to take it away feels terrible.” Mary Bousted, general secretary of the NEU, said: “I’m not selling this as the best deal ever, but given the government we are dealing with, this is a real achievement and I’m very proud of our members.” She added: “We are saying: ‘You can absolutely reject this, but that means committing to multiple days of strike action in the autumn term and the government still won’t budge.’” The Department for Education declined to comment.