Patrick Green, aged 33, befriended the teenager in a Net chatroom called Younger Girls for Older Men. Green, an exports clerk from Buckinghamshire, met the girl on five occasions in real life after a two-month online “courtship” during which he sent his victim a stream of flattering messages.

This story is unfortunately not unique when we come to examine the dark side of the Web.

In May this year, an Old Bailey judge called for a change in the law after a 28-year-old man used the Net to arrange to have sex with a nine-year-old girl for a pound;200 fee. Computer programmer Kenneth Lockley was arrested by undercover police at a hotel after police in America alerted Scotland Yard’s paedophile squad.

Lockley, an pound;80,000-per-year games designer, was jailed for 18 months after admitting inciting another person to procure a girl for sex and distributing indecent photographs of children.

The judge said the law currently meant that while Lockley’s actions were “evil” they were “preparation” - he had not actually met his intended victim.

Therefore, Lockley escaped prosecution for much more serious sexual offences.

Judge Peter Fingret said: “The law does not deal with the type of conduct perpetrated by this defendant. It is time, in the light of the pernicious influence of a large number of websites, that Parliament should consider dealing with this lacuna in the law.”

I dwell on these cases because Internet chatrooms potentially pose the greatest danger to children. But how we control them goes to the heart of a broader issue about how parents and teachers understand the Net. So what do we tell the children?

There are two principal fears about children and their use of the Internet: first, that they will be exposed to obscene material and second, that they will be exposed to a sexual predator who will try to engineer a physical meeting.

Some parents feel understandably baffled by the Internet in general. On the one hand thy realise it is a fantastic educational tool - it can aid homework and promote contact with children globally in undreamed of ways.

ITN’s archive department (www.itnarchive.com) is now providing TV footage to AngliaCampus, an interactive education site designed by teachers and used by 3,000 schools. ITN also provides news to Missdorothy.com, a children’s website which is building a community online. The educational upside of the Web is obvious.

And yet the Net can also potentially plumb your family into a virtual sewer where anything goes.

Unfortunately for parents and teachers, ignorance of the Web is not an option.

Children can find websites with sexual content by either searching for certain keywords, or being accidentally referred by a hyperlink. There are software packages that can block access to websites containing certain “banned” words, but these at best constitute a crude roadblock. Brighter children will always find a way to circumvent them.

There are websites which offer vetted content for children and chat areas like atkidz.com that offer chat sessions monitored by an adult on the alert for untoward conversation.

But there are certain basics that parents and teachers must grasp. Did you know a web browser leaves footprints of the websites a child has looked at? Do you ask your child what sites they visit? Does he or she have a PC in their bedroom?

In the same way children are taught not to talk to strangers, we have got to issue the same code online. Children must know they can’t give out e-mail addresses or other personal details to an unknown person online, however nice they may appear to be.

Talk to your children about their Internet use. Look in detail at a browser, go to chat areas yourself, and study how software filters work.

Yes, the Net can be daunting to grown-ups. But we have to go back to the Internet classroom and study like our children’s lives depend on it. Because one day they might.

Fergus Sheppard is new media-correspondent for ITN and writes a daily column for the ITN website, part of ITN New Media. For the latest multimedia news, visit the ITN site at www.itn.co.uk