A third of Britons who use social networking sites are putting themselves at risk of burglary, an insurer warned yesterday.

Seven out of 10 adults use social networking sites, such as Facebook and Twitter, but many are revealing too much personal information, The Co-operative Insurance said.

Two-thirds of people have posted pictures of themselves on the sites, 60 per cent have disclosed their marital status and 42 per cent have shared their date of birth.

A quarter of people have uploaded pictures of their home or car on to a social networking site, while 14 per cent have made their address available.

The group said that while this information may seem harmless, if it fell into the wrong hands it could enable a fraudster to commit identity theft.

More worryingly, 36 per cent of people use the sites to update people on their whereabouts, while 35 per cent countdown to events such as holidays, potentially alerting criminals to when their home will be empty.

Half of people who use the sites said that while they knew all of their “friends”, they did not see them all regularly, while 21 per cent admitted that while they knew most of them, some were friends of friends.

The group urged people to exercise caution when using social networking sites, only accepting friend requests from people they actually knew, while keeping the amount of personal information they made available to a minimum, and never revealing their date of birth or address.

It also called on people to lock their profiles, so that only people they knew could view their pages.

David Neave, director of general insurance at The Co-operative Insurance, said: “Social networking websites such as Facebook, Twitter and MySpace are fantastic ways of linking up with friends, old and new and sharing news amongst other things. However, these websites need to be used with caution.

“A common sense approach when using social networking websites is key. You have to ask yourself ‘would I be happy to divulge this information normally?’ If not, you shouldn’t make people aware of it online.

“Unfortunately, whilst the majority of people use these websites as they are intended, there is a minority group which will be using them for their own illegal gains and therefore it is very important to be vigilant and err on the side of caution when updating statuses.”

72 Point questioned 3,000 people for The Co-operative Insurance.