AN investigation is underway at the University of Exeter after students were alleged to have been caught having intercourse during a safe sex ball.

The university's students' guild has begun to look into the incident after camera footage from the annual charity event, held just before Christmas to promote safe sex, appeared online.

The four-minute clip shows an apparently naked couple having sex.

A union spokesman said in a statement: "The students' guild recognises that confidential CCTV footage has been filmed without our permission.

"The guild is making sure the affected parties will be supported during this difficult time.

"Measures were in place to provide high levels of security, but we are aware that irresponsible behaviour has taken place and we are working hard to rectify the situation.

"A full investigation is under way in which action proportionate to the seriousness of the situation will be taken."