Muslim women are being asked to tell authorities about relatives who are intending become jihadists by going abroad to fight in Syria's civil war.
British officials are concerned about the number of U.K. nationals traveling to battle President Bashar Assad and fear that they may return home and commit terror attacks.
London's Metropolitan Police, which is responsible for anti-terrorism operations nationally, launched a campaign on Thursday aimed at reaching out to mothers, sisters and wives as well as community groups.
"It is about preventing tragedies"
"We want to ensure that people, particularly women, who are concerned about their loved ones are given enough information about what they can do to prevent this from happening," Metropolitan Police Deputy Assistant Commissioner Helen Ball said. "This is not about criminalizing people. It is about preventing tragedies. We want to inform those who wish to genuinely help the Syrian cause how they can do so safely and legally."
The patchwork of groups fighting Assad has become increasingly radicalized as the three-year-old war has progressed. They include the ultra-extremist Islamic State of Iraq and the Levant, which recently started forcing Christians to live under 7th-century laws and have been known to cut off the hands of thieves in the Syrian city they control.
As many as 2,800 of the rebel fighters are believed to be European or Western, including nearly 400 British citizens. This year alone, 40 people have been arrested in Britain on suspicion of trying to travel to Syria to fight in the conflict.
A new video recently posted on YouTube claims to show a British jihadist in Syria touring a militant base and unveiling the austere living conditions of fighters there. An iPhone and a digital camera can be seen on one bed and the footage includes scattered AK-47s along with vestiges of Western living including a bottle of Tabasco sauce.
U.S., European and Russian intelligence officials fear that terrorists who shuttle back and forth to fight in Syria may pose the next big threat to the West.
The war has shown no signs of resolution after leaving more than 130,000 people dead and millions more forced to leave their homes.
British officials were keen to stress that not everyone traveling to Syria was intent on becoming jihadists, but others were critical of the drive.
Shiraz Maher, of the International Centre for the Study of Radicalisation, told BBC News that the police were "the wrong people to be launching this type of campaign."
He adeed: "That message should be coming out either from community groups or other elements of government."