Hunched in black robes over his microphone, Sheikh Omar Bakri suddenly heaves himself upright in rhetorical climax and pounds the table. "Embrace capitalism or Christianity, you go to hellfire!" he bellows. The crowd of men seated before him nod in agreement as Sheikh Bakri warns against misplaced sympathy for Western society.
"Don't think that because [the unbelievers] give us income support we should have less hate," he continues. "Because we hate not for our sakes, but for the sake of Allah."
His point made, Bakri sinks into his chair and indulges in a bit of Islamist bravado by cracking a dark joke about stabbing people in the guts. A low murmur of laughter passes through the men, while at the back of the room their wives, wrapped in chadors, remain still and silent as columns. A few children scamper in the aisles.
Hard-line Islamists like Bakri have become the bête noire for Britons who question whether the growing ranks of Muslims here want to integrate more fully into society. This anxiety, felt throughout Europe, has intensified after weeks of headlines played up the murder of Dutch filmmaker Theo Van Gogh by an Islamic extremist.
It's an anxiety felt acutely by Britain's 1.8 million Muslims. They are one of the country's fastest-growing, poorest, and least educated minorities. But many are struggling to repair a reputation tattered by home-grown radicals like Bakri and find a place in mainstream society. And despite setbacks to their image, they are making progress.
• Muslim leaders supported a government initiative to filter out extremists by imposing an English test on foreign imams seeking work permits.
• Mosques are transforming themselves into community hubs in an attempt to dampen the mistrust and alienation that observers say can cause some young Muslims to turn to radicalism in the first place.
• Many mosques now host regular interfaith discussions, organize after-school youth groups, and have worked with local police to foster goodwill.
• Muslims voted in record numbers at this summer's European elections, defying both radical imams' and some non-Muslims' view that Islam and democracy don't mix.
"The Muslim community has to stand up and be counted as a British Muslim community," Khurshid Ahmed, spokesman for Muslim issues at the Commission for Racial Equality, told the BBC.
Many Muslims seem to agree. A recent poll commissioned by The Guardian newspaper showed that 33 percent of Muslims wanted more integration into mainstream British culture.
"The generation that's grown up here calls itself British and Muslim," says Imam Yunus Dudhwala, "and I don't think that's a contradiction."
But the same poll showed that 26 percent of British Muslims felt integration has gone too far.
"We have pockets who ... feel that even integration is a threat to their way of life," explains Ibrahim Mogra, head of the Muslim Council of Britain's Imams and Mosques Committee.
Indeed, Muslim parents often worry - with some justification - that their kids will pick up un-Islamic behavior from their English peers.
"Muslim girls aren't supposed to smoke and drink and hang about out on the street like boys," says Ima, a Muslim woman out shopping for a new sari in her Muslim neighborhood.
But when she slips into a side-street for a quick cigarette, she confirms fears that mainstream British culture will corrupt traditional Islamic values.
At the same time, moderate Muslims worry that the British media's focus on the few bad apples creates a false, sinister image of all Muslims.
"The reality [of extremism] is that there is almost nothing there," insists Inayat Bunglawala, spokesman for the Muslim Council of Britain, the country's foremost Muslim lobby group. "The rhetoric about the Great Satan and the Islamic superstate can seem daunting. But it's just rhetoric."
Yet a handful of British Muslims have turned such rhetoric into action.
• In 2001, Richard Reid, a British convert to Islam, boarded an American Airlines flight with shoes packed full of explosives. (Crew members restrained him before he could set them off.)
• In 2003, two British Muslims blew themselves up in a Tel Aviv bar, killing three and wounding 55.
• British-born mujahideen were found fighting for the Taliban in Afghanistan.
• Last spring, British police foiled a massive bombing plot by Muslims targeted inside Britain.
• And three British Muslims are alleged to have joined the radical insurgency of Al Qaeda affiliate Abu Musab al-Zarqawi in Iraq.
Although some blame the media, many Muslims - especially younger ones - complain that their community lacks unity and strong leadership.
"I don't think there are inspiring spokespeople for mainstream Islam, and that's a major problem," says Wasif, who runs a graphic design business.
Above all, moderates say, mainstream Muslims must confront the extremism that has taken root in Britain.
"Much of the Muslim leadership has not only denied the problem, it has maligned and ostracized those who have attempted to address it," stormed Fareena Alam, the managing editor of the Muslim magazine Q-News, in a column for The Observer newspaper last April.
Muslim leaders are beginning to respond. Mosques have adopted a policy of vetting would-be imams and blackballing radicals like Bakri, who are forced to preach in hired halls.
Affirming British identity is what mainstream Muslims claim they must do if they are to capture the limelight from the extremist minority and shake off the stigma of terrorism.
But for integration efforts to bear fruit, the British public will have to take notice. "Non-Muslims need to have an open mind," says Bilal, an Islamic studies student, "and we need to be better examples."