More than a third of kids in UK secondary schools have been sent messages containing sexual content, a survey has found.

Researchers found youngsters are being sent sex texts or "Sexts" - often by their school friends. The messages contain images of sex acts involving young people and of youngsters exposing themselves. Material is sent to mobile phones via texts, transferred using Bluetooth or uploaded to social networking groups.

The survey was conducted by the children's charity Beatbullying. It found it was most often not strangers sending the images. Seven out of 10 of the 11-18-year-olds surveyed said they knew the sender personally. Only a quarter of the messages were sent by the youngster's current boyfriend or girlfriend. The charity insists that girls are bullied into taking, and sharing, explicit pictures of themselves. Because girls don't do that sort of thing.

Chief executive Emma-Jane Cross said politicians must pool together organisations like Beatbullying to create an intervention and prevention task force in schools and the local community. After all, telling teenage kids what to do is an extremely effective method of controlling them.

“This needs to be part of the solution if we are to educate our young people about the consequences of their actions and how to keep safe online as well as offline," she said.