British spy chief says Islamist militants can execute deadly attack plans in just days

LONDON – Britain faces the most acute threat ever from Islamist militants seeking to inflict mass attacks, often with spontaneous plots that take just days to bring to execution, the head of the MI5 domestic intelligence agency said on Tuesday.

After four militant attacks this year that killed 36 people in Britain - the deadliest spate since the London "7/7" bombings of July 2005, MI5 chief Andrew Parker said the threat was at the highest tempo he had seen in 34 years of espionage.

"The threat is more diverse than I have ever known: plots developed here in the UK, but plots directed from overseas as well, plots online, complex scheming and also crude stabbings, lengthy planning but also spontaneous attacks," said Parker.

"Attacks can sometimes accelerate from inception, through planning, to action in just a handful of days," he said in a speech in central London. The director general of MI5 rarely gives public speeches. The last was in 2015.