In a speech from the security agency's Thames House headquarters in London on Wednesday, Mr McCallum set out in stark language the dangers faced from Russia, China and Iran as well as going over terrorism threats posed to the UK by Islamic extremists and right-wing extremists.

In a speech from the security agency's Thames House headquarters in London on Wednesday, Mr McCallum set out in stark language the dangers faced from Russia, China and Iran as well as going over terrorism threats posed to the UK by Islamic extremists and right-wing extremists.