The application, which follows a long campaign by the Child Exploitation and Online Protection Centre (CEOP), appears on a user's profile page when they add or bookmark it and allows children and teenagers to report suspicious or inappropriate behavior.
Particularly aimed at users aged 13 to 18, it also provides help, advice and support about staying safe online.
An automatic message will appear on the Facebook homepage of all teenage users, inviting them to add the application.
Pressure to introduce such measures intensified toward the end of last year after 17-year-old Ashleigh Hall was kidnapped, raped and murdered by a man posing as a teenager whom she had met through Facebook.
"Together we have developed a new way of helping young people stay safe online," Joanna Shields, Facebook's vice president for Europe, Middle-East and Africa, said of the link-up.
"It is only through the constant and concerted efforts of the industry, police, parents and young people themselves that we can all keep safe online.
The Child Exploitation and Online Protection Center, a government law enforcement agency, has been after social networking sites to provide protections for its underage users. Social networking sites, says CEOP, provide comparatively easy venues for child predators. The agency has seen some success--Bebo and MySpace already adopted the panic button--but Facebook resisted for a long time, saying its own protection was sufficient.
But, reports the BBC, after the rape and murder of a 17-year-old by a 33-year-old who met him on Facebook, CEOP had enough momentum to renegotiate with Facebook. Now, Facebook announced that they'll integrate the panic button as a downloadable application--it won't be built in, but it'll be easily gotten.
Jim Gamble, Ceop's chief executive, said in a statement: "Our dialogue with Facebook about adopting the ClickCeop button is well documented - today however is a good day for child protection."By adding this application, Facebook users will have direct access to all the services that sit behind our ClickCeop button which should provide reassurance to every parent with teenagers on the site."The new app reports both to CEOP and to Facebook, which does of course have its own built-in security systems. The app, called ClickCEOP, will be available in the UK--CEOP is a British agency--but it's not hard to imagine this kind of feature spreading to other countries as well.