The police’s Child Exploitation and Online Protection (CEOP) Centre receives 400-500 reports a month relating to child sexual abuse online in the UK. In 2008-09, 22 per cent of those related to abuse via social networking sites, up 50 per cent from the previous 12 months.

Half of the centre’s investigations are related to online grooming.

Vicky Gillings, a spokesman for the centre, says: “It is every parent’s nightmare that their child might be in danger in their home. That is why giving children the skills to navigate the online environment is crucial.

“Just as you teach children to cross the road, they need to be equipped to deal with their online world, and know how to report a problem.

“Most grooming takes place in a public environment such as Facebook and other social networking sites.

“Predators identity a vulnerable child then encourage them into a more private area of communication, such as texting, instant messaging or e-mailing, where there is less danger of being detected.”

One in four children say they have gone to meet someone they first met online. Most said that they had taken a friend — thus endangering not one but two children.

Advice for children

Keep personal information personal. Do not share your home address, e-mail address, instant messenger ID or full name.

Remember that if you post a picture or video online, anyone can share or change it, and it may be online for ever.

Be aware that people online lie about their age and gender. Be wary of anyone you don’t know in the real world.

If you do go to meet with someone you have met on the internet, take an adult with you. If you take a friend you risk putting both of you in danger.

Be aware of the report button linked to the Child Exploitation and Online Protection Centre, which can be found on many social networking sites. It gives advice and an opportunity to directly report worrying behaviour, which can be dealt with immediately (see ceop.gov.uk and thinkuknow.co.uk )

Advice for parents

Try to know what your children are doing online and who they talk to.

Ask them to teach you to use applications such as social networking sites or online chat rooms.

Make sure your child feels comfortable in being able to come to you, or someone they trust, if they are worried about anything online.

Teach young people how to block someone online and report them if they feel uncomfortable.

Most sites will have guidance on this and a link to the Child Exploitation and Online Protection Centre

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