JFS has been accused of party-pooping by bringing forward study leave for GSCE students in order to prevent the recurrence of a “muck-up” day.

On muck-up days, students traditionally let their hair down and play pranks.

But a number of Year 11 pupils said they were told last Friday they should not come in as planned this week except to attend a leaver’s breakfast on Thursday.

In an email to parents, headteacher Rachel Fink said that study leave would start early to ensure students “maximize the time they need to study”.

The vast majority of Year 11s had been focused on their learning, she said.

“Sadly this has not been true of every individual. Therefore an additional reason to start study leave early is in order to avoid students making poor choices regarding how to spend their final few days in school.”

She said she was “endeavouring to ensure that nobody behaves in such a way that they later come to regret or that may cause damage either physical or reputational to the school. This has not been an easy decision to make and I know that it may disappoint some students. However, I believe it to be the correct one.”

But one pupil said his friends were “extremely outraged as we have been looking forward to muck-up day ever since our first day of JFS - and not to mention watching the legendary muck-up day of 2015”.

Four years ago, the entire Year 11 group was sent home by the school after events were said to have got out of hand. Several pupils were later barred from sitting their GCSEs over their involvement in the day's "loutish and dangerous behaviour".

Reports emerged of fireworks brought on premises, egg and flour fights in classrooms and school property damaged. The antics of a few students were criticised by some sixthformers.

But the Year 11 pupil this year said that although some had talked of bringing in water balloons and water guns, “we wanted to use the amphitheatre  - which we have been banned from since the beginning of Year 10 - one last time and have a relaxing last day before exams.

“Our plan was not to terrorise the school but to say thank you and goodbye and leave a good legacy of our year behind.”

He complained that “my father and his friends have told me about their muck up day. I believe a muck up day is more than just messing around and having a laugh, it is something you will never forget and something Iwant to tell my kids and their friends about like my dad did. But now I won’t have the chance.”

Another student in the year group said some of her peers were “crying” after being told of the school’s decision last Friday. “They have done this in fear of muck up day, however there has been no proof of any plans for muck up day besides rumours,” she said.

A third student said: “For most, the last day of school would just have been a chance to say goodbye to friends and teachers as well as a positive way to alleviate the stress  of our upcoming GCSEs, however now we don’t have a chance for this and are being thrown into our exams."

JFS has been approached for comment but had not replied as this article went live.