State multiculturalism has failed and left young Muslims vulnerable to radicalisation, the British prime minister David Cameron will say today, arguing for a more active policy to heal divisions and promote Western values.
Mr Cameron, in a speech to a security conference in Munich, will argue that Britain and other European nations need to "wake up to what is happening in our countries" as well as tackling terrorism through military operations overseas.
"It is time to turn the page on the failed policies of the past," he will say, according to extracts from his speech released by his office.
"So first, instead of ignoring this extremist ideology, we - as governments and societies - have got to confront it, in all its forms."
His comments echo those made by German leader Angela Merkel last year and reflect a push by European governments to better integrate immigrants, given persistent domestic tensions between different cultures.
Mr Cameron will also deny that cuts to defence spending as part of efforts to tackle a record budget deficit mean that Britain was retreating from an "activist" global role.
"That is the complete reversal of the truth," he will say. "Yes, we are dealing with the deficit, but we are also making sure our defences are strong."
Aides say his comments on multiculturalism and radicalization give a direction of travel for future policy, and it remains unclear how the Conservative-Liberal Democrat coalition intend to turn his vision into a reality.
Critics point out that Western foreign policy in the Middle East and beyond, not just a clash of cultures at home, has played a big part in stirring up anti-Western sentiment.
"Under the doctrine of state multiculturalism, we have encouraged different cultures to live separate lives, apart from each other and the mainstream," Mr Cameron will say.
"We have failed to provide a vision of society to which they feel they want to belong ... All this leaves some young Muslims feeling rootless."