Britain’s leading role in NATO’s war against Russia in Ukraine and the military targeting of Iran ensured that McCallum’s remarks led the front pages of four major UK newspapers.

In a rare public speech setting out the major threats to the United Kingdom, Ken McCallum argued that hostile states, radicalized individuals, and a revived Islamic State group have combined to create “the most complex and interconnected threat environment we’ve ever seen.

Russian military intelligence is seeking to cause "mayhem" across Britain and Europe, the UK's domestic spy chief said on Tuesday, while a growing threat from al Qaeda and Islamic State was his greatest terrorism concern.