Providers of online services should offer alert systems and filtering mechanisms to protect children, according to best practice guidelines issued by the government to clamp down on internet paedophiles.
The Models of Good Practice offer advice to providers of internet chat, instant messaging and other web-based services, to make them safer for children.
The guidelines were drawn up by the government's Internet Taskforce on Child Protection, which includes representatives from government, the internet industry, child welfare organisations and the police.
In a statement Home Office minister Hilary Benn said: "We are aware of the potential for paedophiles to misuse modern technology to abuse the trust that children place in them by attempting to 'groom' them through chat rooms.
"We want to encourage parents to help their children protect themselves so they can surf safely."
Nicholas Lansman, secretary general of the Internet Services Providers' Association (ISPA), said: "Just like the offline world, the online world has its hazards.
"The publication of this good practice shows ISPA's and the government's commitment to making the UK the safest place for children to go online."
The government has also launched a £1m 'safer surfing' advertising campaign to warn of the dangers of internet paedophiles, but without demonising the internet itself.
A series of television adverts will run throughout January, supported by radio and online advertising, to encourage parents to make sure their children understand the dangers of communicating with strangers online.
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