Genial and polite, the boys gave up their seats to two elderly ladies who had boarded the London Underground train. These nice young lads then spent the rest of the journey in a gleeful discussion about the destruction and disarray they had recently wrought at their school in the name of “muck-up day”.

I was not shocked that seemingly pleasant young men would glory in such things. I have seen for myself across a number of schools how otherwise charming and considerate students often consider it their right to vandalise their schools on their departure at the end of Year 11 or Year 13. And although it may seem early to start thinking about this end-of-term anarchy, it is not: now is the time to begin planning.

The lighthearted pranks of urban legend - such as the releasing of sheep labelled 1, 2, 3 and 5 to ensure the hunt continues even when all the livestock are recovered - are, in my experience, outnumbered by incidents that are not only witless but also upsetting and intimidating for school staff, other pupils and members of the public.

One of my previous schools took extreme action to prevent muck-up day by keeping the date on which Year 11 were to go on study leave a secret, with not even the staff being informed. Towards the end of the day, midway through a lesson, the head of year turned up and asked me to escort my GCSE history set to the hall. Once the whole year group was there, they were informed that they would be escorted to the front gates in ones and twos. That was the end of that. While effective, it was rather brutal: many students left the premises in tears.

One of my previous schools kept the date on which Year 11 were to go on study leave a secret

I sympathise with teachers who feel that this is the only course of action available to them. Social media means that footage of muck-up days can go viral, with children seeking to copy or outdo what they have seen online. Check out the hashtag #MuckUpDay for yourself to see what I mean.

When I took charge of two year groups at one school I worked in, muck-up day had been a growing issue. My initial response was to abolish it through sheer force of planning. I organised a whole day of intensive English and maths revision, with students walked between the rooms by staff in small groups. I identified individuals that I thought might present a problem and requested that their parents escort them to the school. And I lectured the year group before the day about how it was all for their own good. In one sense, it worked. The day passed without incident on our site.

However, at a time of year when teachers and students most needed to work together, the resentment young people felt at having been “robbed” of muck-up day spilled out in other ways. Clocks started to go missing around school and our pastoral teachers became preoccupied by the investigation.

It also turned out that, to make up for the lack of mayhem, the bulk of the year group headed to one of their peer’s houses for a party, a mere 36 hours before their first GCSE.

Community spirit

The next year, I decided to take a different approach. The first step was to move the day. A colleague had already suggested phasing in study leave and continuing the Year 11 timetable in the early weeks of the exam period. This proved highly effective: teachers gained more contact time at a vital point in the year. And when optional subjects such as history or Spanish were taking place, the reduced class sizes allowed for interaction that was rarely possible with a full compliment.

With no clear “last day” of Year 11, we made the final day of the spring term the students’ last day. This was already a half day, and also one on which motivation was likely not to be at its peak, so impact on profitable teaching time was minimised.

After going to regular lessons, in the final period, all Year 11 students came to the main hall. They signed each other’s shirts, ate a goodbye brunch and watched a presentation produced by their peers with pictures of their year group throughout the years. I also had a surprise for them.

I collected ‘You Make Us Proud’ letters from every parent

Wanting the day to be special, and to send the students off in the best frame of mind possible, I had collected “You Make Us Proud” letters from every parent - an idea that Chris Edwards, then deputy headteacher at the Magna Carta School, had adapted from the England rugby team. Almost every student was oblivious, with one who had rumbled the plan keeping quiet to save the surprise.

As at my previous school, there were tears, but far happier ones. Many students kept their letters on their desks throughout May and June to help maintain their motivation to revise.

Muck-up day is a too-often-subverted expression of a year group’s sense of community. The good news is that it can be channelled into something memorable for students, parents and teachers - and for all the right reasons.

Andrew Foster is head of education at Tougher Minds and tweets @AFosterTeach