A furious headteacher has fired off a no holds barred letter to parents accusing one of “harassing” pupils over the school’s academy plans.

Simon Langton Girls' Grammar in Canterbury head Jane Robinson claims stickers have appeared around the school which read “Robinson hates grammar schools – don’t let her ruin Langton” and “Don’t let the Gestapo silence us”.

The school has stoked controversy by proposing a switch to academy status.

A government white paper had previously suggested state schools would eventually be forced to convert to academies should they not do so voluntarily.

The school's plans have prompted a group of parents to set up a campaign group to fight the proposals.

But in an impassioned response, Mrs Robinson is accusing a “small minority” of parents of punching below the belt.

In her letter, she accuses one unnamed parent of a Year 8 pupil of tweeting fellow year 8s urging them to join the campaign against academy plans.

“This is being treated very seriously as harassment as it is worrying to our younger students in particular and we would urge all parents to report any such issues to the school,” Mrs Robinson writes.

“This parent should not be putting your daughters in such a position and it is entirely inappropriate.”

She also accuses “unidentified individuals” of seeking to organise a protest on school grounds on Monday.

She writes: “Several of our students have come to us with this news, and they are really upset and quite angry that this should have been proposed, particularly at a time when the examination classes are in the final stages of preparing for their exams and have enough stress in their lives without any distractions such as this.”

Commenting on the stickers, Mrs Robinson says the messages were "deeply shocking and upsetting, most particularly when our students do not behave in such a way, and have been set up to do this by a very few parents who should know better".