Members of a campaign group ­opposing plans to apply VAT to ­private school fees have targeted the ­education ­secretary Bridget Phillipson with ­personal abuse, accusing her of aping the ­tactics of Nazi Germany and labelling her a “vile hag”.

A bitter row has emerged over the government’s proposed policy, amid claims from ­opponents that it will increase class sizes in state schools as some parents will no longer afford fees when 20% VAT is added to them in January.

However, a series of messages on the private Facebook group run by the campaign body Education Not Taxation: Parents Against School Fee VAT (ENT), seen by the Observer, ­levelled personal attacks on Phillipson, with some calling to picket one of her constituency events.

The most extreme messages ­compared the VAT policy to the ­persecution that took place in Nazi Germany. One message read: “1930s Germany targeted the Jewish ­minority on the basis of their perceived privilege Bridget Phillipson. Just like you going after the 500,000 children in private school. Who cares though eh? Firstly they are only 7%, and secondly, they are not Keir Starmer’s kids.”

In response, another member replied: “Well said”. Another ­intervened to add: “Nobody is ‘going after’ the children of the top 7% (and certainly not quite in the same way you are implying).”

A separate message stated: “Nazi Germany again?”

Phillipson is also described as a “horrible woman”, the “queen of mean”, an “absolute bitch” and “scum”. Plans were discussed to gather ­outside a constituency event “with signs”, with a member saying: “I do hope some can attend and give her ‘what for’ with both barrels.” Another said: “I hope one day you [Phillipson] rot.”

Group organisers said they did their best to moderate comments, but as a voluntary organisation that was not always possible.

However, the comments highlighted by the Observer are now being removed. A warning post is already in place ordering members not to ­publish degrading posts.

“The highlighted posts do not reflect the overwhelming ­majority of discussions on the Facebook page, which are civil and focus on the real harm this policy is ­causing to ­thousands of families,” said Loveena Tandon, spokesperson for the group. “We regularly remind our 23,000-plus members to keep posts respectful.

“While we do our best to ­manage over 1,400 comments daily, it’s a challenge without dedicated staff. We do not condone the language in these posts and work hard to moderate content according to our values.

“We are also deeply concerned by the divisive stance taken by education secretary Bridget Phillipson and the Labour government, which is ­‘othering’ independent school ­children, fuelling abuse and creating a toxic environment.

“We urge the government to end this harmful rhetoric and meet with parents affected by the proposed policy. Despite several requests, we have yet to secure a meeting with the education secretary.”

Some users in the group also documented the steps they were having to take to pay for the increased fees. One said they had “cancelled RSPB and my national trust membership”, another said that they had dropped work on a kitchen and a third that they had “cancelled a new driveway”.

Ministers say the money raised from the VAT hike will be spent on 6,500 new teachers, better mental health support for children and breakfast clubs for all primary schools.

Those opposed to the policy have warned that the plans are rushed, state schools will see an influx and that children with special educational needs and disabilities will be affected, as will children from military families and those from small religious faiths.

The Independent Schools Council (ISC), which had quoted the campaign group in some of its social media posts, distanced itself from the­ ­abusive comments.

“The ISC has no official involvement with ENT,” it said. “We do not condone offensive or abusive remarks – these have no place in this discussion. We utterly condemn the distasteful language used in the comments highlighted by the Observer.

“In addition to being objectionable, these posts draw attention away from the very real and legitimate concerns parents have about the future of their children’s education.

“We will continue to raise these concerns in our efforts to urge the government to delay the implementation of VAT on fees and to mitigate its impact on schools and families.”