Right-wing extremists have defended the attack in London on 19 June, in which a man deliberately drove a van into a group of Muslim worshippers after late-night Ramadan prayers, by claiming: ‘This is war: we have the right to fight back’. There are concerns that British authorities are ‘way behind’ the increasingly sophisticated tactics used by such extremists to radicalise followers online. They now cover their tracks by using untraceable mobile phones and services that conceal their computer’s location - leaving the police unable to find them. They have also used less regulated social networks like the Russian-based VKontakte (VK) service to build up ‘spider’s web’ groups of like-minded individuals who then support and radicalise each other. Meanwhile, many Muslims have expressed fears that they are not safe, and the Muslim Council of Great Britain has called for extra security around mosques, describing the attack as ‘the most violent manifestation’ of Islamophobia.