They once plotted insurrection in Britain. Young, middle-class, and angry, they were the vanguard of a generation of disaffected Muslims that, at its most extreme, gave rise to the July 7, 2005, transportation bombers.
But now, in one of the most visible assaults on political Islam from within the British Muslim community, a network of ex-radicals launched on Tuesday a movement to fight the same ideology that they once worked to spread.
The Quilliam Foundation – named for a 19th-century British convert to Islam – aims to propagate a tolerant and pluralistic view of Islam among young Muslims who are the most vulnerable to radicalism.
"We are trying to rescue our faith from those who have sadly hijacked it," says Ed Husain, author of "The Islamist," a book about his own radical years, and deputy director of the foundation. "There is a Western Islam in the making and it is not arrogant or extreme."
Mr. Husain has said that as long as Islamist militants provide "social honor" for suicide bombers and spuriously use doctrine to justify violence and political aims, "then we will continue to see mass murderers being respected as martyrs."
Guided by mainstream Muslim scholars and supported by prominent politicians and academics, the group of around a dozen ex-radicals plans to expose what it calls the weaknesses of Islamist rhetoric and actions – in short, to recapture Islam from the ideologues and terrorists.
"We are trying to fill a vacuum. The ideology of Islamism has sadly become the default for political discourse among young British Muslims," says the foundation's director, Maajid Nawaz, a former radical who until last year was a leader of the Hizb ut-Tahrir (Liberation Party) group, which wants to revive an international caliphate across the Muslim world, although it advocates doing so through nonviolent means.
Aside from think-tank work of getting their ideas into the public domain, the foundation also plans to set up a task force of ex-radicals who can "go to the hot spots and work on the grass roots to deradicalize people and the contacts that we have known in these movements for a long time," Mr. Nawaz says.
Yet in the complex constellation of ever-changing British Muslim movements, it is too early to say whether the Quilliam Foundation will prove to be an effective and exemplary voice that resonates with the wider community.
Some critics have warned that it is just another stripe in the colorful and contrasting rainbow of Muslim opinion in Britain. Others say that they are "defectors" who have moved to the mainstream where they will have little chance of appealing to young radicals.
"They will have a hard time reaching out to people who are actively involved in extremist organizations," says Peter Neumann, director of the International Centre for the Study of Radicalisation and Political Violence in London. "But they probably do have the capacity to go into schools and certain other environments and have some leverage there because they are Muslims who were involved in radical activities."
"Therefore if there are people that have the platform and the ability to challenge and expose myths that Al Qaeda purveys then that is very important and significant," he says. "It is pivotal to win hearts and minds and to prevent new generations of young impressionable people from joining terrorist groups. The language of hate has to be countered with the language of moderation and reason."
But he adds that Quilliam, which is funded by private donations, will have to prove its financial independence to keep its integrity intact.
The initiative comes at a crucial time in Britain's struggle with radical political Islam. A spate of arrests, terrorism trials, and convictions may give the impression that the authorities are coming to grips with extremism, but security services still warn of at least 2,000 dangerous Islamists on their radar.
The home secretary, Jacqui Smith, signaled last week that Britain could not arrest its way out of the terrorism threat. "We need to prevent people from becoming terrorists and supporting terrorists in the first place," she said. "That means challenging the sort of ideology that supports terrorism."
Mr. Neumann says the government is disillusioned with established groups like the Muslim Council of Britain (MCB) for failing to combat extremism – both vocally and effectively.
Quilliam says it can succeed where the MCB has failed because of the personal narratives of its leaders. Nawaz spent 12 years in Hizb ut-Tahrir after turning to the movement out of disaffection with the racism and discrimination that poisoned his teenage years in southeast England.
His story is typical of the drift into radicalism that overcame many young British Muslims who rejected the conformity of their parents and turned to firebrand rhetoric and intoxicating ideas of ideologues.
There were secret meetings, conversion missions, evangelistic forays to university campuses and foreign countries. But after more than four years in an Egyptian jail, Nawaz says he had the time to reflect on the true meaning of his faith.
"I began to realize that what I had subscribed to was actually Islamism sold to me in the name of Islam," he wrote recently. "And it is with this realization that I can now say that the more I learnt about Islam, the more tolerant I became."