Quarter of under-13s on Facebook, MySpace or Bebo

Facebook, MySpace and Bebo all have a minimum age limit of 13, but research by Ofcom shows a quarter of 8 to 12 year olds who use the internet have a profile on one of the social networking sites.

Of those, 17 per cent of their parents admit they're unaware what their children are up to online.

An annual audit into children's media literacy by the communication watchdog also unveiled just how web-savvy youngsters can be, however, with 83 per cent setting their profiles so only friends can access their details.

The findings are likely to fire up the already heated debate around the Facebook panic button nonetheless.

In recent weeks, the site declined to install the abuse-reporting mechanism sought by campaigners, which would link up to the Ceop (Child Exploitation and Online Protection) centre.

While Facebook requires that potential account owners reveal their age, there is no verification measure to ensure it's correct.