Russia, Iran and China have fuelled a dramatic rise in the threats posed to the UK from foreign states, the head of MI5 has warned.Sir Ken McCallum said the number of individuals being investigated for involvement in "state threat activity" had increased by 35% in the last year.

Russia, Iran and China have fuelled a dramatic rise in the threats posed to the UK from foreign states, the head of MI5 has warned.Sir Ken McCallum said the number of individuals being investigated for involvement in "state threat activity" had increased by 35% in the last year.