Headteachers have reacted with anger after the government ratcheted up pressure on schools to remain fully open in the run-up to Christmas, threatening legal action against a London council after forcing two others to back down. On Tuesday evening, Islington became the latest to retreat after a letter was sent by the government. It told the Labour-led authority it should reconsider its decision to advise schools to move to remote learning or it would risk the legal consequences. Richard Watts, leader of Islington council, said: “Coronavirus cases are rising fast in Islington and London, and following public health advice about this very serious situation, we originally advised schools in Islington to move to online learning. “After discussion today with the Department for Education, we have now advised our schools to open as usual to pupils on Wednesday.” Schools will be able to have inset – or training – days on Thursday and Friday so pupils do not need to attend. Waltham Forest in east London had also been sent a strongly-worded letter reminding it of its duty to keep schools open until the end of term. A more conciliatory letter was sent to Basildon – which comes under Conservative-led Essex county council – where a significant number of schools have closed amid rising infection rates, but there has been no blanket agreement for schools to move online. Clare Coghill, leader of Waltham Forest council, later said the authority had not received correspondence, but was aware that schools minister Nick Gibb had written to all schools across the borough threatening legal action if they fail to remain open. “It is disappointing that, during a year when teachers, pupils and parents have made extraordinary efforts to ensure education continues through a once-in-a-lifetime crisis, the minister has chosen to write to our schools threatening them with potential legal action,” she said. “We will continue to do all we can to support schools to make the decisions that will safeguard the health and safety of pupils, teachers and their families and ensure children continue to be educated.” Earlier, Greenwich reluctantly backed down after the education secretary, Gavin Williamson, launched legal action on Monday night. Williamson issued a “temporary continuity direction”, demanding the immediate withdrawal of a letter issued to headteachers advising them to close schools early and switch to remote learning. School leaders and teaching unions described the government’s approach as “appalling”, “shameful” and “a step too far” at the end of a term that has been hugely challenging for schools. The row overshadowed an announcement about the rollout of mass testing to all secondary schools in England from the start of the new year. Kevin Courtney, joint general secretary of the National Education Union, said local authorities that decided to move schools and colleges to online learning a few days before the end of term did so in the face of rising infection rates and for the safety and protection of their communities. Children of keyworkers and vulnerable pupils would continue to go to school. Courtney said: “The fact that Gavin Williamson and the prime minister refuse to see sense and allow the professional judgment of headteachers and local authorities to take precedent is shameful and yet another grave error of judgment in a long line of such errors. “They should hang their heads in shame. Parents, students and school staff will not forgive this wilful neglect of their safety.” Secondary schools, primaries and colleges in Greenwich will fully reopen for face-to-face teaching until the end of term later this week. In a letter to parents, the leader of Greenwich council, Danny Thorpe, said he could not agree that this was the best choice for schools in the borough, but neither could he justify using public funds to fight a court battle with the government. “Consequently, I have no choice but to ask our schools to keep their doors open to all students,” he wrote. The education secretary welcomed the decision, adding: “The regional schools commissioner and her team will continue to work with schools in the borough, as we are with schools across the country, to make sure they have the support they need.” The government’s mass testing plans, which should have been a good news story, prompted further criticism from exasperated unions. They said schools had been given no notice and accused the government of supplying tests but not the staff, training or supervision to carry them out effectively. Under the new proposals, supplies of rapid-result lateral flow tests will be delivered from the start of next term to all secondary schools, colleges, special schools and alternative provision in England. Primary schools will follow later. Staff will be invited to have weekly tests, and staff and students who have been in contact with someone who has tested positive will be eligible for daily testing for seven days to enable them to remain in school if negative. “The use of lateral flow tests in schools has potential to make a positive impact by helping to break chains of transmission early,” said Paul Whitehouse, the general secretary of the National Association of Head Teachers. “But this requires not only sufficient tests but also the trained staff to administer them.” The Department for Education said schools would be provided with personal protective equipment as well as guidance and training materials. Geoff Barton, the general secretary of the Association of School and College Leaders, said it was an “unseemly” end to a gruelling term when schools should have been allowed some flexibility rather than faced with legal threats. “That will not be easily forgotten.” He said many parents would keep their children at home regardless, and though he welcomed testing he added: “It isn’t perhaps the ideal moment … when schools and colleges are already under massive pressure on multiple fronts.” Williamson said: “This huge expansion of rapid testing for those working in education is a milestone moment in our work to keep schools and colleges open for all.”