In Great Britain, a 30-year-old policy of multiculturalism — favoring cultural diversity over integration — has created ethnic enclaves where old-world rules often conflict with those of the new homeland.

Most of the residents in these enclaves are law-abiding citizens, but the recent London transit bombings, carried out by British citizens, have highlighted a growing concern among many Britons about cultural assimilation and exactly what it means to be British.

"Everybody was entirely relaxed with the idea of Britain becoming the ultimate melting pot with no particular central core uniting it," said John Kampfner of The New Statesman (search).

A recent poll found that 46 percent of British Muslims feel more Muslim than they do British. This has many people concerned that after many generations of Muslims being in Great Britain, there should be a greater sense of loyalty to the British state.

"Those ideas of patriotism, nationalism, being loyal to your country, are drilled into school children in America and to a lesser extent Canada at a very early age. I don't think that happens in this country [Great Britain]," said Hamida Ghafour (search), an Afghan-born author who grew up in North America.

According to Ghafour, radical clerics prey on that void — preaching sedition instead of citizenship.

"You see, if you want to win the heart and mind of Muslim youth, you want to speak the language of Koran,” said Omar Bakri Mohammed (search), an anti-British Muslim cleric. “You want to tell them 'God said do so' or 'God said don't do so,' not because Tony Blair (search) said or the queen said."

Most Muslim leaders say that the British government is doing a lot to help communities better integrate into the mainstream, but it could do more. And those living in the Muslim enclaves say that their communities could do more as well.

"It's absolutely imperative that Muslims, young Muslims, old Muslims, engage more with the mainstream, engage more in public and political life," said Hanif Abeel (search) of the group Muslim Friends of Labor.

Click in the box near the top of the story to watch a report by FOX News' Amy Kellogg.