UK terror threat level 'severe'

The UK's terror threat level has been raised from "substantial" to "severe" in response to conflicts in Iraq and Syria, Home Secretary Theresa May says.

The new alert level rates the risk of an attack on the UK "highly likely", although May said there was no evidence to suggest one was "imminent".

It is the second highest of five possible UK threat levels.

In a Downing Street press conference yesterday, the prime minister said Islamic State (IS) extremists - who are attempting to establish a "caliphate", or Islamic state - represented a "greater and deeper threat to our security than we have known before".

He said that "learning lessons from the past doesn't mean there isn't a place for our military" in combating the threat, but did not commit to any military action.

He added the "threat is growing" from Britons travelling to fight with IS, saying at least 500 people had travelled from the UK "to fight in Syria and potentially Iraq".