Facebook has caved in to continued pressure from child protection groups and launched a limited 'panic button' service for teenagers in the UK.
The button will be targeted particularly at 13 to 18-year-olds, with an automatic ad appearing on the home page of users in this age group inviting them to add the application.
It will report to a government agency, the Child Exploitation and Online Protection Centre (CEOP), as well as to Facebook itself.
There's also a new CEOP Facebook page, which will contain polls, news alerts and status updates and will link to questions about online safety.
"I strongly urge parents to encourage their children to download this application now," says Minister for Crime Protection James Brokenshire.
"It’s a sad fact that we are now seeing more cases where sex offenders are using social networking sites to conceal their identities in order to contact children."
CEOP had been calling for the installation of a panic button since last year, prompted in large part by the murder of 17-year-old Ashleigh Hall by a convicted sex offender who befriended her on Facebook posing as a teenage boy.
However, Facebook insisted that current reporting systems were adequate.
"Our dialogue with Facebook about adopting the ClickCEOP button is well documented – today, however, is a good day for child protection," says Jim Gamble, CEOP chief executive.
"We know from speaking to offenders that a visible deterrent could protect young people online. We urge all Facebook users to add the app and bookmark it so that others can see that they’re in control online."
The app falls short of the full panic button service which CEOP was calling for, as it's optional and does not link to the police. It's also a UK-only initiative, at least for the time being.