IS menace causes UK to raise terror threat level from 'substantial' to 'severe'

David Cameron said the threat was growing because of Britons travelling to fight with IS

In the wake of growing conflicts in Iraq and Syria, the UK has raised its terror threat level from "substantial" to "severe".

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

Britain Prime Minister David Cameron said in a press conference on Friday, the Islamic State (IS) extremists represented a greater and deeper threat to UK's security than it was known before.

He said that learning lessons from the past did not mean that the British army did not have a place when it came to combating the threat.

However, he refrained from committing to any military action.

The British PM added that threat was growing because of Britons travelling to fight with IS.

He said that at least 500 people had flown from the UK to Syria and Iraq to join the jihadist group.

He assured new legislation would make it easier to seize passports from those travelling to the two countries to fight along side the IS.

The UK government has reportedly increased security and protection measures following the raised threat level.