Meanwhile, The Telegraph reports that up to 450 radicalised Britons have returned to the UK from Syria. Scotland Yard is investigating 600 terror cases related to Syria and Iraq. From "about 750 [british citizens] of interest to the security and intelligence services", who had gone to Syria "about 60% have returned", Charles Farr, director of the Office for Security and Counter-Terrorism said. He added that people, who can't travel to Syria or Iraq from the UK, have been told by Isis to stay and "undertake attacks". http://www.ibtimes.co.uk/paris-attacks-elite-sas-srr-forces-deployed-uk-streets-counter-isis-terror-threats-1528800 why on earth are they able to come back?