The prime minister will criticise "state multiculturalism" in his first speech on radicalisation and the causes of terrorism since being elected.
Different cultures are encouraged to live apart, and objectionable views met with "passive tolerance", he will say.
"Frankly, we need a lot less of the passive tolerance of recent years and much more active, muscular liberalism," the prime minister will say.It's fashionable (and fairly easy, too) to be cynical about the Coalition and their lack of delivery of all the things that many were hoping for in the new government. But it's a long time since I have heard a British Prime Minister uttering such sentiments, and expressing them in such unambiguous terms. Rome wasn't built in a day, and at least it's a start. I am mildly encouraged.
A genuinely liberal country "believes in certain values and actively promotes them," Mr Cameron will say.
"Freedom of speech. Freedom of worship. Democracy. The rule of law. Equal rights, regardless of race, sex or sexuality.
"It says to its citizens: This is what defines us as a society. To belong here is to believe these things.
"Each of us in our own countries must be unambiguous and hard-nosed about this defence of our liberty."
He will say that under the "doctrine of state multiculturalism", different cultures have been encouraged to live separate lives.
"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."