For six years they have done exactly what they are told but for one day the Year 6 youngsters at Redland School in Chippenham let rip with every naughty deed they could think of – and their headteacher was delighted.

Each year the school has a leavers’ assembly to say farewell to its oldest pupils and as part of this year’s the youngsters, aided by Year 6 teachers Ronnie Joy and Kath Thomson, produced a four-minute video accompanied by Pharrell Williams’ hit song Happy.

It featured the school’s top set of youngsters wreaking havoc.

They were asked by the two teachers to come up with ideas for all things they have been stopped from doing during their time at the school and were then filmed doing them.

They were shown dancing around the school hall, messing up notice boards, throwing paper around, riding on tea trolleys and switching around labels on drawers.

It was all a shock to headtecaher Hilary Lambert, who saw it for the first time alongside fellow staff and parents at the leavers’ assembly. “I couldn’t believe what I was seeing,” she said. “I was overwhelmed. I was roaring with laughter because it was so wonderfully put together. There was no malice intended, it was just good clean fun.”

Even Mrs Lambert’s admin staff Lin Paynter and Fran Bowling got in on the act when they were seen swigging from a wine bottle in the office.

Senior teacher John Smith, a noted stickler for neatness, didn’t escape the spoof with pupils taking great delight in mixing up his neatly-ordered pencils.

One youngster was even caught with his feet up on Mrs Lambert’s desk.

She said: “Everyone loved every minute. The kids got a little bit of revenge on us all but it was just so funny. I was crying with laughter but there were a few genuine tears too because it was quite poignant. We’ve seen them all grow up here.”

The video has more than 1,300 views on YouTube. See it at gazette&herald.co.uk