Londonistan

Just in case the Brits hadn't figured that out, the usual anonymous U.S. State Department official was happy to do it for them. Last month, an official told the Daily Telegraph that their country "has the greatest concentration of active al Qaeda supporters [in the West]," posing a threat to Britain and "the rest of the world." The same article cited a fresh and ominous finding from the director of MI5. He estimated his service was aware of some 2,000 "radicalized Muslims" who might be involved in terrorist plots. That figure, of course, doesn't include the population of plotters who have escaped MI5 scrutiny, like Abdulmutallab. As if to underline the threat, on Jan. 12, the British government banned two of the country's most notorious Islamist organizations, Islam4UK and Al Muhajiroun, under a 2000 anti-terrorism law.

So why is this particular front in the war on terrorism proving such a challenge? Haras Rafiq, a British Muslim who founded a think tank to combat Islamic extremism, worries that a big share of the blame goes to his own government. For decades, he says, Britain tolerated plotting by domestic Islamic radicals as long as they targeted other countries, often ones in the Middle East. "We gave them freedom to preach violence and extremism -- [as long as] they were preaching it abroad and not in the U.K. They used that freedom to take over community organizations, mosques, TV stations," he says. "They've been building capacity for their viewpoint." He describes the radicals' techniques as strikingly reminiscent of those of 20th-century communists and fascists. The Islamists have also mimicked the Irish Republican movement by using ostensibly non-violent political groups to covertly radical ends.