His three Islamia schools might be prepared to take in non-Muslim children but more competition for places will not go down well with parents. Applications already outnumber places by 10 to one.

The singer formerly known as Cat Stevens chairs the Islamia Schools Trust, which in 1983 founded the first Muslim primary school in London. In 1998 the primary became the first Muslim school to join the state sector.

The experiment has been encouraging enough for its partner secondary schools - Islamia girls, founded in 1989 and Brondesbury college for boys, opened in 1995 - to also contemplate state funding.

“It’s made us more conscious of our relationship with other schools in the area and with the council and in a broad sense it’s helped our school to integrate,” Mr Islam says.

“We’d still be shouting on the steps of the town hall - now we can go straight in.”

The three schools have around 470 pupils. All are Muslim. At the primary, places go first to “Muslims of commitment”. Around a quarter go to pupils with social need, like those from single-parent families. After that, it’s applicants with siblings at the school and those who live closest.

But the secondaries are both selective and fee-paying - pound;3,800 a year for the girls’ school, pound;4,800 for Brondesbury with its new science block. Pupils must pass a test covering English, maths, science and Islamic studies.

That helps explain the schools’ results - it claims 100 per cent of pupils got five GCSE grade Cs or better this year. It also explains how a private, fee-paying, selective school like Brondesbury can persuade Ken Livingstone to present the prizes at its annual prize-giving.

The schools and the Mayor of London have a mutual affection that goes back to the 1980s. “You have always been a friend of Islamia School, and all the children think you’re really cool,” pupils sing as he is shown round.

Mr Livingstone is equally effusive. “Here in this school you produce children with a moral code and a sense of right and wrong,” he said in his speech. Brondesbury was “an example to all schools in Brent”.

But while he wants to see “a string of Muslim schools in London”, he is clear, too, they must take in local children of other or no faiths. “We don’t want ghettoisation,” he tells The TES.

In fact, far from creating an insular enclave, Yusuf Islam sees the schools’ mission very much in terms of the wider world. He says this as an adult convert. The Koran enshrines tolerance to other faiths, he says. “People that came to this country as Muslims maybe haven’t been able to understand that principle. I think we’ve been rather insular. The time has come for Muslims to be more proactive - to get involved more.”