UK will not be safe from ISIS until their ‘virtual caliphate’ is destroyed, warns Theresa May’s security adviser

Britain will not be safe from Islamic State terror attacks while the extremists’ “virtual caliphate” survives, one of the Prime Minister’s top security advisers has warned.

Patrick McGuinness said that as the remnants of the area under the militants’ control – self-described as the ‘caliphate’ – are swept from Iraq and Syria, the web has now become the front line against the group.

Counter terrorism experts told a conference at the Royal United Services Institute in London that the priority was to now destroy the “virtual caliphate”