Clearing up was taking place at a Suffolk academy today after former students having a last look round their old school decided to cause mayhem.

Hundreds of adults aged from 20 to 80 turned up for the open evening at the old Orwell High School in Felixstowe – staged because the building, currently one of the campuses of Felixstowe Academy, is set to be closed and demolished when a new £20million academy opens next month.

But while the vast majority enjoyed looking around their old alma mater, seeing the memorabilia, and being reunited with long-lost friends from their school days, a small minority of the grown ups decided to turn back the years – deciding school was out forever.

The group – 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 to the campus in Maidstone Road, and the building had to be evacuated.

It meant the evening had to be cut short, too, as no-one could be allowed back inside because emergency fire systems had to be disabled while firefighters checked out the classrooms, corridors and workshops.

A smiliar event planned for the old Deben High School in Garrison Lane tonight has been cancelled.

A police spokeswoman said officers were initially called to the school at around 7pm last night to deal with parking problems and then helped with the evacuation of the building after alarms were deliberately activated.

Officers are currently investigating incidents of criminal damage.