Passed pupils were invited to have one last look round their old school, Orwell High School in Felixstowe in the UK. Some of the people who came along clearly never grew up and decided to return to their old ways by scrawling grafitti, letting off fire alarms and smoking in the toilets.

Police and firefighters had to be called to the school that had been left open for a special evening before the school was evelled to make way for a new academy.

Most apparently enjoyed looking around their old alma mater, seeing the memorabilia, and catching up with long-lost friends from their school days.

But a minority - said to be in their 40s and 50s - deliberately and repeatedly set off fire alarms, scrawled graffiti on walls and desks and were caught smoking in the toilets.

Lewd pictures were drawn on walls, and it is understood some of the current students' work was damaged. Police and fire crews were called and the building had to be evacuated.

Jaimielee Rendall, who left the school in 2005 and now works for BBC Radio Suffolk, said most people were well behaved but some had been drinking since mid-afternoon.

"I've heard various stories that people were walking around drunk and didn't know what they were doing," she said.

Felixstowe Academy said in a statement that "hundreds of people" had attended the event to look at archive material and meet with former teachers and school friends.

"Sadly a very small minority of adult visitors took it upon themselves to smoke within the building and write graffiti on the walls, causing vandalism to an operating school."