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.
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.