New MI5 chief spent first 10 years of his career tackling Northern Ireland terrorism

A man who spent a decade combating Northern Ireland terrorism has been appointed as the new director general of MI5.

en McCallum takes over from Sir Andrew Parker, who retires in April having been in charge of the organisation since 2013.

Mr McCallum has 25 years' experience in MI5, and has also worked on Islamist extremism and cyber security.

He said: "MI5's purpose is hugely motivating.

"Our people - with our partners - strive to keep...