MI5's Ken McCallum warns of Russian chaos, Iran plots, rising terror threats, and increasing youth radicalisation in the UK.

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.

The head of Britain’s domestic security service said Russia’s military intelligence service was pursuing “dangerous actions conducted with increasing recklessness.”