Ken McCallum says agency facing ‘one hell of a job’ to counter efforts to stage assassinations and terror attacks

The head of MI5 has said his agency has “one hell of a job” to do as the threat from Islamic State has returned while both Iran and Russia engage in intensifying efforts to undertake assassination and sabotage plots in the UK.

Ken McCallum said a revival of IS in Afghanistan in particular had brought a resumption of efforts by the Islamist group to export terrorism, and a “bit of an upswing” in Britons seeking to travel abroad to learn from the group.