Hundreds of teachers are risking their careers through inappropriate use of social networking websites at school, The TES reveals today.

Staff using sites such as MySpace are being urged by internet experts and teaching unions to think twice before they log on. Social networking is the latest on-line craze, allowing teenagers and adults to share friends, music and gossip.

But school staff could unwittingly be giving pupils access to details about their private lives, or having inappropriate conversations with them.

Recent studies show that 16 to 24-year-olds prefer social networking websites to watching television, with 70 per cent accessing sites and 54 per cent using them regularly.

Up to 61 per cent of 13 to 17-year-olds have personal pages on social networking websites.

Steve Sinnott, general secretary of the National Union of Teachers, said:

“One of the problems with these sites is the anonymity because you don’t have to use your own name and nor does anyone else you are talking to.

“You need to be aware of that so that you don’t walk into any sort of trap.”

Sercurus provides electronic systems to more than 500 schools allowing them to monitor computer-use by pupils and staff, and check for abusive and threatening language, swear words, paedophilic grooming and other improper on-line behaviour.

Derek Allen, one of the directors, said it had seen a 50 per cent increase in the number of violations in the last 18 months, with teachers committing an average of more than 10 a week.

“My advice to teachers is be extremely careful about who you are talking to and what you are saying,” he said.

“The chances are that if they are saying something inappropriate then they will be caught.”

The unions agree. “Keep your private life private and maintain your own privacy,” said Mr Sinnott.

A spokeswoman for the Association of Teachers and Lecturers urged education staff to be cautious and use common sense about where and how they revealed information.

Ruth Hammond, from the British Educational Communications and Technology Agency, said: “Anybody who uses these sites has got to be aware that they are about children and adults mixing together.

“Once you have posted something online it is there forever and whether you are telling it to 10-year-old, a 17-year-old or a 50-year-old you have to be careful of what you are saying.”

* william.stewart@tes.co.uk