The subject also comes up next door in the mosque's office, where Sheikh Suleman Gani and the mosque secretary, Farouk Valimahomed, have laid out tea and biscuits for me. "One Muslim brother came up to me in the station. He was very angry about what has happened to our Muslim brothers, and I had to calm him down. I told him that this is a time of testing," said Valimahomed. "In every community, you find a small group who commit crimes. And in the Koran it says don't make the whole people responsible for a crime which one individual has committed."

The strain on community leaders like Valimahomed is evident. "People who had never identified with Osama bin Laden are now thinking again as the news comes - Bush's agreement with Sharon, the Israeli assassinations of Hamas leaders, now the photographs. You begin to think there is more to it; I never used to consider there was any justification for Osama bin Laden, but now I'm not so sure. A lot of people feel the US is out for revenge for 9/11."

"There's a pattern of abuse in Guantánamo, Belmarsh. There's more to come out in Afghanistan and Iraq. At first we were doubtful, but it's all coming together," said Gani. In their eyes, the "pattern of abuse" has come all the way to the quiet terraced streets of Tooting. Last December, four youngsters were arrested. In the close-knit Muslim community, the details of the police operation, with helicopters and dozens of police in the night, spread like wildfire. There was considerable publicity surrounding the arrests, but none around their subsequent discharges, and the damage was done - Muslims felt threatened, and they also felt their standing in the neighbourhood was irreparably harmed.

"At a meeting for youngsters of the mosque last winter, I said to them, 'Don't be vociferous, don't talk on the pavement outside the mosque, don't hold extremist views, don't say too much on your mobile phones, because something could happen in this area'," said Valimahomed. But they didn't like what they were being told. "One said, 'It sounds like you are restricting our freedom.'"

Iqbal Sacranie, secretary of the Muslim Council of Britain, has invested over 30 years of his life building up Tooting and its parent mosque in nearby Balham. In that time, Muslims have achieved something not far short of miraculous: self-financing mosques that serve as community centres for thousands of families, running women's health groups, offering advice, education and police drop-in sessions. But now Sacranie and other community leaders find themselves in an increasingly precarious position, having to assure the police and Home Office of their cooperation, on the one hand, and reassure their own community, on the other.

"We have to convince two sets of people. If the government doesn't listen to our points about how and why they make these arrests, then our community asks us, 'What are we getting out of the relationship with the authorities?' They want to see results," says Sacranie. "During the arrests last December, one grandmother of a suspect, in her 80s, was very worried. She asked me, 'Are we all targets now?' I assured her, no, that wasn't the case and I would help."

The issue for Sacranie, Valimahomed and others like them, is how long will they manage to keep the community's trust? The pressure is enormous; there have been 562 arrests since 9/11 under anti-terrorism legislation and only 97 charged. Plus, there has been a huge increase in the use of stop and search under terrorist legislation. In jeopardy are the achievements of a quarter of a century of dogged work to establish a strong, peaceful British Muslim community. In Tooting, the mosque's schools integrate Muslims from every part of the globe - from Nigeria to Turkey and Afghanistan - and make them British. The little five-year-olds in their veils, caps and turbans, their faces beaming, recite English nursery rhymes, while their 15-year-old counterparts upstairs are poring over the Merchant of Venice.

For the past decade, the classrooms have been shoehorned into an old cinema and double up as the mosque at prayer time. Yet their Sats and GCSE results have been spectacular. Most of the children have English as a second language, yet by age 11 they achieved 100% at the government required reading level in 2003. They have finally been granted state funding, and the £7m purpose-built primary school is to open its doors - to Muslims and non-Muslims alike - in September. Kangat dreams of a Muslim sixth-form college, Muslim teacher training and a Muslim university - an entire Muslim educational system. Valimahomed talks of the sports academy they are developing on a 38-acre site for Muslims and non-Muslims.

The struggle by Muslims to establish their own institutions and identity in this country, in the face of hostility and suspicion, is comparable to that of the Catholics at the time of the Irish independence movement in the late 19th century. But the stakes are higher, and the international context and its global repercussions more insistent. So, where are their allies? Who's helping? In the US, interfaith groups have mushroomed in a bid to build understanding between Christianity and Islam, and there have been comparable initiatives here, but they are less significant in a secularised Britain. The allies one might expect on the liberal left hold back. They find the religiosity alienating, they can't get beyond the hijab issue, and in many quarters they're no longer prepared to take up the cudgels on human rights - accepting the government line that such is the threat of terrorism that some rights have to be curtailed.

What the Muslims in Tooting most want is understanding of their faith - of its principles of community, peace and its abhorrence of violence. The same message was evident at an event in central London last week, addressed by the American Muslim convert Hamza Yousef. Over a thousand young Muslims turned up to discuss "Islam, citizenship and the west". There's a battle going on as to what kind of a religion Islam is; schools, public debates and clinics rarely make headlines, while bombs always do. Too many non-Muslims have listened only to the terrorists and have already closed their eyes and ears.