The body representing independent schools in the UK has described the shadow education secretary as “very chippy” in private messages, as it steps up its campaign against Labour’s plan to add VAT to school fees. A public access request to the Independent Schools Council about Bridget Phillipson revealed that officials said she “doesn’t know diddly” and suggested she should “appreciate the great good our sector does”. In a sign of their more aggressive tactics as Labour moves further ahead in the polls, the lobby group has written to the party’s MPs with private schools in their constituencies to warn them of the impact of the policy on pupils’ families. It has also sent an email, seen by the Guardian, to independent schools predicting that it is looking “increasingly likely” that Labour will come to power at the next general election and that the VAT policy could cause “damage” to their sector. One letter gives schools a template that Labour insiders suggest could be shared with parents to try to discredit the party’s policy, including details of, for example, how much the ISC claims the local state education system saves as a result of private schools existing. It has prompted warnings from party figures that they could write to the Charity Commission about any independent schools – which are exempt from VAT and some other taxes due to their charitable status – that express political opinions or conduct a political campaign. Labour has pledged to use about £1.7bn generated from ending private school tax breaks to recruit more than 6,500 new teachers and give every child access to a mental health counsellor at school and professional careers advice. The party wants to make state schools more attractive to middle-class parents priced out of private education by focusing on activities such as debating and the arts alongside high academic standards. A Labour source said: “For too long the Conservative government has failed abjectly to be the kind of determined advocate that state school-educated children and their families badly need to break down barriers to opportunity in this country.” The public access request was submitted to the ISC last November after education experts criticised Jeremy Hunt’s use of data from the leading private school lobby group to justify his decision not to raise £1.7bn by adding VAT to school fees. ISC officials said Phillipson was “clearly annoyed” that the Treasury “got away with” pointing to research provided by the group after the shadow education secretary accused the chancellor of “shamelessly” using the data to justify his actions. Before a media appearance with Phillipson, one official emailed: “I think she has no independent schools in her constituency so she doesn’t have the real experience you have. She is bound to peddle the Labour lines off-pat.” A further email said: “Essentially, her line is that independent schools are for the rich and that they are flourishing at the expense of state schools. It’s an us vs them thing (which I think is covered by the class war answer below). She gets very chippy when people don’t agree with her or push back at her, so it is very easy to make her sound unreasonable by keeping your cool.” Officials defended their data, which has been criticised by experts, in internal ISC WhatsApp messages from January 2023. “With all due respect to the shadow SoS [secretary of state], our numbers are right and beyond reproof and she don’t know diddly,” one said. And in March, another official wrote: “I do wish Bridget Phillipson would take a moment to appreciate the great good our sector does. It’s so disappointing that Labour doesn’t grasp it. Saddening.” An ISC spokesperson said: “Schools are engaging with their local MPs over a policy that they are extremely worried will impede their charitable work. They are perfectly entitled to do so under Charity Commission rules, and the threat to silence independent schools’ right to object to a tax that would do very real harm to them and their local communities is both empty and cynical. “ISC has been consistently clear that it is opposed to the Labour party’s stated policy on independent schools, not the Labour party itself. Indeed, ISC would welcome the opportunity to work with the Labour party to build on the good work already being done in the sector, instead of Labour penalising parents with a tax on their choice of school.”