Outside a small, red-brick mosque, a young Muslim in sneakers and a white robe is lecturing a cluster of young men gathered on the sidewalk.
"The London bombings ... were about striking terror into the heart of the enemy," he thunders, just one week after the 7/7 attacks that killed 56 people and wounded hundreds more.
Muslims around the world are being slaughtered, he tells them. "All we ask them is: 'Remove your troops from Muslim lands and we will stop all of this.' " The men nod in agreement. One glances into the baby stroller he's pushing. Car after car races past.
The preacher, who calls himself Abu Osama ("Father of Osama"), is one of a new breed of British radicals thriving at the margins of London's Muslim community.
Young, independent, and streetwise, they are preaching in urban slang outside the confines of Britain's mosques. They are helping teens and 20-somethings beat drugs and alcohol. And they are inspiring a new pool of impressionable young Muslims to consider killing their fellow Britons.
These radical bands constitute a small fraction of London's 1 million Muslims. But their freewheeling ideology - hardened in the jihadi echo chambers of cliques like Abu Osama's - is creating a new subculture within Britain's Islamic community. So far, the growing influence of these informal, maverick groups has gone largely undetected - and unchecked.
As older, camera-courting, foreign-born extremists like Omar Bakri and Abu Hamza al-Masri recede from relevance, their younger counterparts are striking out quietly and independently with a new brand of do-it-yourself radicalism.
"On the ground level, people like Bakri don't communicate with the youth," says Nadim Shehadi, an analyst at Chatham House, a think tank in London. The fragmentation of British radical groups and their dispersal underground, he adds, is the "worst of all possible options."
"When the Muslim Council of Britain [MCB] said 'We must be vigilant,' this pushed [radical groups] underground," says Abdul-Rehman Malik, contributing editor at the Muslim magazine Q-News, based London. As radicals fled to minor mosques and homes, Britain's security services, and even mainstream Muslims, lost track of them.
Did the 7/7 bombers come from Bakri's circle? "Probably not - it's something far more insidious," says Mr. Malik. "It's beyond the Omar Bakris; it's a low rumble."
Abu Osama, just 30, was born and raised here in East London, amid peeling paint and dingy kebab shops. "I know English. I know Britain. But if I live here, I must speak for Muslims elsewhere," he says, stressing that he belongs first to the ummah, or global Islamic community.
Abu Osama's faith deepened early. Watching his Pakistani immigrant father struggle to support his family of seven, he sought strength in Islam.
"I began praying and studying when I was 16, and since then I've been like this," he says, pointing to his long, curling beard.
Abu Osama first spoke publicly eight years ago; he has since won ardent followers.
Last fall, addressing a meeting of scores of British radicals, he sighed: "At the moment in Britain there is no jihad." Faces fell around the hall.
"Yet!" he exclaimed suddenly, to approving murmurs. The jihad would soon come, Abu Osama predicted, and he urged his listeners to embrace its arrival.
On 7/7, the jihad came. The suicide bombers were aged 18 to 30 - the same age as Abu Osama's cohorts. By portraying militancy as the ultimate expression of piety, Abu Osama and preachers like him are leading young Muslims down the path toward violence.
"Some of the people tell you Islam is a religion of peace because they think that then you'll want to convert," says Dublin-born convert Khalid Kelly, who soaks up Abu Osama's sidewalk sermon. "But you cannot possibly say Islam is a religion of peace; jihad is not an internal struggle."
Armed struggle was the last thing on Mr. Kelly's mind until his conversion several years ago. "I was your average Irish drunkard, partying and so on," he says. Arrested in Saudi Arabia, where he worked as a nurse, for brewing his own alcohol, Kelly found Islam in prison - an increasingly common arena for Muslim conversion and radicalization.
After his return to Britain in 2002, Kelly quickly became a disciple of Bakri, a radical Syrian-born cleric based in Britain, who is most widely known for celebrating 9/11, and more recently, blaming 7/7 on British foreign policy. Through Bakri's circle, which is now largely underground, Kelly met Abu Osama. Now, they gravitate toward obscure mosques that nurture homegrown extremists.
"The imam here" - Kelly nods at the mosque - "said, 'Pray for the victory of the mujahideen in all the world.' He's talking about Osama bin Laden, but he can't say that."
Hard-line mosques are an intoxicating arena for disillusioned young Muslims, Britain's fastest-growing, poorest, and worst-educated minority.
"The pull to Islam in general is not bad," says Malik. "It gives [young people] a sense of identity and spirituality that is important to their lives."
However, the perceived persecution of Muslims worldwide can imbue their faith with a politics of resentment; they see the world divided into two opposing groups: Muslims and others. "The world begins to appear black and white," Malik says.
"When it comes to politics, sometimes I just feel angry," spits Farouq (not his real name), 21, as he scans East London shop-windows for Help Wanted signs. Women in chadors sweep past, steering their baby carriages through discarded fish'n'chips wrappers and cigarette ends.
Farouq has never heard of Abu Osama. "I don't have time to pray any more. But I'd like to get back into it," he muses. "I know definitely [Islam] will help me."
Concerned that radical groups might capitalize on this kind of discontent, mainstream Muslim leaders have deliberately shunned those who advocated violence.
Some say the effort to weed out extremists is a sign of progress. Others say it has backfired, throwing together vulnerable young Muslims and hard-liners.
This week, British Prime Minister Tony Blair met with Muslim leaders to discuss ways to confront this "evil ideology." As Mr. Blair pushed legislation to deport radical clerics, the group announced plans for a task force and clerics pledged greater cooperation with security officials. But analysts say mainstream clerics may struggle to reach young Muslims already committed to radical ideology.
Kelly, evidently, had little use for the summit: "You're either a servant of Tony Blair, or Islam."
Last fall, Inayat Bunglawala, a spokesman for the MCB, told The Christian Science Monitor that the extent of radicals in Britain was being hyped up by the media. "The reality on the ground is that there is almost nothing there," he said. "Islamic terrorism: much of it is a media myth."
Then came the slaughter of 7/7. From cafĂ©-studded central London, mainstream Muslim organizations declared that such suicide attacks were un-Islamic.
But over in East London, Abu Osama's group argues that attacks on civilians by Palestinian, Kashmiri, and Iraqi militants are seen as legitimate by the majority of the world's Muslims.
"How dare anyone come on television and say suicide bombings are not part of our belief?" scoffs Irish convert Kelly. "These [moderates] are the lunatic fringe!"
Radical Muslims like Kelly consider themselves an embattled vanguard of the "true" Islam.
"We are persecuted for telling the truth, just like Jesus," says Kelly. "They're demonizing us. There's always police. They tell us it's for our own protection, but it's obvious they're here to spy on us," he adds.
"All we want to talk about is how beautiful Islam is," says an Iraqi immigrant, who, like others standing here, mingles lyrical spirituality with a blunt advocacy of violence. "Zarqawi is showing the way," he says, referring to the Jordanian militant Abu Musab al-Zarqawi, leader of the radical faction of foreign fighters in Iraq.
Like many, his dedication to Islam arose from a messy flirtation with a Western lifestyle, including drinking and taking drugs. "When reality hits you, you come back to Islam," he says. "If you read the Koran, you see that Allah gave us the right to terrorize the enemy."
His disillusionment with Britain became complete when he was sacked from his IT job "for telling a kafir [unbeliever, or non-Muslim] woman to cover up." Ironically, only Abu Osama dons religious garb. The others wear jeans and shirts. Kelly would look at home in an Irish pub.
They aren't the only British Muslims torn between two worlds. Every year, many young British Muslims visit the Middle East to explore their roots and often to study Arabic and Islam in a traditional environment. Most return to the West, their curiosity satisfied, to continue their lives. A few, by accident or design, return deeply transformed.
Several of the 7/7 suspects, too, are believed to have traveled to Pakistan, where investigators believe they may have hardened their faith. Officials are also exploring whether the four suspects made contact with an Al Qaeda aide linked to Mr. Masri, the radical cleric.
British-born radicals "would have felt a secret excitement of having become the spearhead of a mission that would make them renowned in martyrology," says Magnus Ranstorp, director of the Centre for the Study of Terrorism and Political Violence at St. Andrews University, Scotland.
But despite this bleak outlook, even such conservative Middle Eastern countries as Saudi Arabia and Yemen have successfully defused the anger of Islamic militants through an intensive program of religious dialogue and youth outreach.
At the East London mosque, Abu Osama's street preaching has evolved into a theological debate: Should one defend Islam worldwide by fighting in Britain? For these men, it's not just a philosophical exercise. Their conclusions could tip the balance of security across the country.
"Islam is not just a religion. It is a way of life," insists a young and zealous black American convert initially drawn to Islam by admiration for Malcolm X. "It's specific in the Koran that jihad is about fighting."
"If you're in Iraq," Kelly affirms, "it means physical fighting."
The Iraqi breaks in. "Every day I think of going there. But Allah has to choose me. I pray to Allah that I can go there one day and help them." The others pause, digesting his words.
"We are torn between these two worlds: a love for life, and a love for death," he continues. "I have four children. I can't leave them. My children will be led astray if I leave them."
He may not have to, Kelly suggests: "We can fight wherever, in Iraq, London, Paris, or Berlin. There is no such thing as innocents. The idea of the Islamic state is terror against anyone who doesn't support Islamic ideology."
Abu Osama nods. "If four men can take explosives and rock the whole of Britain, imagine what more could do."
Shahid: An Islamic martyr. Often used to label Muslim victims of wars, terror attacks, and assassinations.
Halal/Haram: Permitted/forbidden according to Koranic law. Observant Muslims forego cigarettes, alcohol, and nonmarital sex. Most Muslims also avoid pork.
Dar al-Islam/Dar al-Harb: "House of Islam," where Koranic law prevails; and the "House of War," meaning everywhere else.
Kafir: Unbeliever, non-Muslim, one who refuses to submit to Islam.
Jihad: The term means "struggle in the path of God." Muslims debate whether jihad means a purely personal struggle within oneself for right thoughts and deeds, violent struggle in the name of Islam, something in between, or both.
Takfir: Literally "rejection," but in radical circles refers to the branding of other Muslims as unbelievers to discredit them.
Dawah: Islamic call or propagation. Inviting another to Islam; missionary work.
Ummah: The worldwide spiritual community of all Muslims.
Jahiliyyah: Ignorance of Islam; "barbarism." Some radicals use this term to describe Western society.
Fatwa: An Islamic scholar's legal opinion about whether something is permissible. Usually on mundane topics, but radicals have issues death-sentence fatwas against opponents.