A MUCH stronger British identity needs to be forged to stop young Muslims being radicalised and tempted into terrorism, David Cameron will tell a counter-terrorism conference today.

In a speech to the 46th Munich Security Conference, the Prime Minister will say the "doctrine of state multiculturalism" has failed as it has encouraged people from different cultures to lead separate lives.

He will criticise a "hands-off tolerance", that means objectionable practices like forced marriage often go unchallenged.

This approach, he will say, has left some young Muslims feeling rootless while what is needed is a "much more active, muscular liberalism" to promote British values and a sense of belonging.

Mr Cameron's remarks are likely to spark some controversy, and come 24 hours after leaked documents revealed a stark warning from MI6 that the UK faced a unique threat from home-grown terrorists, which would "not go away any time soon".

British-born terrorists were behind the July 7, 2005, London Underground bombings. The four bombers were radicalised and had terror training abroad.

In his speech, the PM will say the root of the terror threat is Islamist extremism, but he will make clear it is vital to distinguish this from Islam.

"Islam is a religion observed peacefully and devoutly by over a billion people. Islamist extremism is a political ideology, supported by a minority," he will say. "Time and again people equate the two.

"They think whether someone is an extremist is dependent on how much they observe their religion. So they talk about moderate Muslims as if all devout Muslims must be extremist. This is wrong. Someone can be a devout Muslim and not be an extremist."

Mr Cameron will argue young Muslims are drawn to extremism because they do not identify themselves with traditional Islam practised by their parents, or with Britain because "we have allowed the weakening of our collective identity".

He will say: "Under the doctrine of state multiculturalism, we have encouraged different cultures to live separate lives, apart from each other and the mainstream.

"We have failed to provide a vision of society to which they feel they want to belong. We have even tolerated these segregated communities behaving in ways that run counter to our values."

Mr Cameron will claim that if a white person holds racist views they are rightly condemned but when equally unacceptable views or practices come from someone who is not white, "we have been too cautious, frankly even fearful, to stand up to them". He says the "horrors of forced marriage" are a case in point.

"The hands-off tolerance has only served to reinforce the sense that not enough is shared. All this leaves some young Muslims feeling rootless and the search for something to belong to and believe in can lead them to this extremist ideology."

The Prime Minister will point out how the extremist distortion of Islam must be challenged by those within Islam too and he will also confront long-standing British attitudes.

"Frankly, we need a lot less of the passive tolerance of recent years and much more active, muscular liberalism."