While welcoming new governmental recommendations to protect children surfing the web, one of the UK's largest children's charities has warned that the measures may not work.

The NSPCC has stated firmly that the Home Office recommendation that those on the child sex offenders' list be forced to hand over their email address to police so that they can be blocked from social networking sites, will have a limited effect.

Zoe Hilton, NSPCC policy advisor, has told journalists: "It [the policy] is not going to stop anyone who is going to target children and it's not going to make the internet safe".

And she added that the plan is focused just on the UK so it will not going to stop sex offenders abroad targeting children in this country.

However, she did add that the charity sees any government moves to help protect children online as positive: "We do broadly welcome this. In general this is a good step to make sex offenders think that it's harder to target children".

The measure, which is expected to affect around 30,000 offenders, is expected to be put in place by the autumn.