Although he is facing criticism at home and throughout Europe – both from the left and from the right of the political spectrum, he is right to raise the issue and open debate. Too many people feel uneasy about extremism.
Marx called nationalism 'the aching tooth' of any social-minded person: how you react to 'national' vs 'human' defines you as a political animal. Accepting and respecting different cultures within one nation does not mean accepting antagonistic values. Excluding minority cultures is dangerous, even destructive – to the same degree and as much as rejecting your adopted nation's mainstream culture.
He is said to have consulted with German Chancellor Angela Merkel on the contents of his speech.
Germany faces similar problems with the rising influence of the right, on the one hand, and extremism among young immigrants.
Excerpts from the BBC report on Cameron's speech in Munich:
David Cameron has criticised "state multiculturalism" in his first speech as prime minister on radicalisation and the causes of terrorism. At a security conference in Munich, he argued the UK needed a stronger national identity to prevent people turning to all kinds of extremism, BBC reports.
He also signalled a tougher stance on groups promoting Islamist extremism. The speech angered some Muslim groups, while others queried its timing amid an English Defence League rally in the UK. As Mr Cameron outlined his vision, he suggested there would be greater scrutiny of some Muslim groups which get public money but do little to tackle extremism. Ministers should refuse to share platforms or engage with such groups, which should be denied access to public funds and barred from spreading their message in universities and prisons, he argued.
"Let's properly judge these organisations: Do they believe in universal human rights - including for women and people of other faiths? Do they believe in equality of all before the law? Do they believe in democracy and the right of people to elect their own government? Do they encourage integration or separatism? These are the sorts of questions we need to ask. Fail these tests and the presumption should be not to engage with organisations," he added.
In the speech, Mr Cameron drew a clear distinction between Islam the religion and what he described as "Islamist extremism" - a political ideology he said attracted people who feel "rootless" within their own countries."We need to be clear: Islamist extremism and Islam are not the same thing," he said. The government is currently reviewing its policy to prevent violent extremism, known as Prevent, which is a key part of its wider counter-terrorism strategy.
A genuinely liberal country "believes in certain values and actively promotes them", Mr Cameron said.
He said 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." Building a stronger sense of national and local identity holds "the key to achieving true cohesion" by allowing people to say "I am a Muslim, I am a Hindu, I am a Christian, but I am a Londoner... too", he said.
"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."(I am writing a separate blog on the source of 'muscular liberalism' mentioned in Cameron's speech, pleace come back to read).
And this is a satirical take on 'I'm a Londoner' theme by the Muppets: