But it was the lessons of this school trip to the country, and of his primary school in the East End of London, that came back to Ed Husain when he was in the grip of fanaticism almost a decade later.

Ed became attracted to extremism while still at secondary school. Feelings of isolation and of not belonging helped propel him towards the radical group Hizb ut-Tahrir. The group, which has been banned in many Arab countries, rejects democracy and has as its goal the unification of the Muslim world in a state ruled by Islamic law.

By the time he went to sixth form college, he says he was fully involved in the group’s activities, promoting religious intolerance, spreading anti-Semitic propaganda and recruiting fellow students to Islamism, political Islam.

Ed, now 31, has written about his journey to extremism and back in his controversial book The Islamist, a voyage which had its roots in his experiences as a Bangladeshi growing up in the East End. He says British Asian children were regularly the victims of racist abuse. Trips to the library involved running a gauntlet of skinheads.

It was his primary school, Sir William Burrough in Tower Hamlets, which gave him his first positive experience of multiculturalism in the 1980s. And it was his school that took him on his first trip to the English countryside, although only after Susy Powlesland, the headteacher, had visited his parents to reassure them that he would be able to observe his halal diet. He says that holiday gave him a taste of what the world could look like.

“It proved genuine multiculturalism works,” he says. “These were my best childhood memories: it was a genuinely pleasant experience and a bit of freedom. It illustrated to me that human beings from different backgrounds can live side by side and not be in conflict. It helped me form a belief in Britain. Later in life, when I doubted my affinity with Britain, those memories came rushing back.”

He particularly credits his primary school head for instilling this belief. Susy, now retired, says these school trips - and the approach at Sir William Burrough - formed part of their determination to provide a positive experience.

“We had a very strong ethos about valuing the whole child, not separating their academic achievements from their social self,” she says.

“We never deliberately set out to teach ‘Britishness’, but I suppose the majority of teachers were white British, so perhaps the children developed positive associations. These things are better caught than taught, in my experience.”

She recalls the everyday racism experienced by some of her pupils. “There was a little local park that was totally out of bounds for Bangladeshi kids. I couldn’t bear that so I used to go there with them but even then it wasn’t comfortable. I often thought, ‘What if there is a backlash?’ After all, these children are going to grow up one day.”

For Ed, that backlash was swift in arriving. After Sir William Burrough, he went to Stepney Green Secondary. Although the pupils were largely Bangladeshi, many were relatively recent arrivals and had little in common with a Bangladeshi who had been brought up in Britain.

“I’ve never identified myself as Bangladeshi - I was born here, raised here and didn’t visit Bangladesh till I was 19 and that was only to see my grandparents,” he says. In his isolation, he turned to religion, and befriended another pupil who led him towards extremism.

By 16, he says he had no white friends at all and had to make a choice between Asian street gangs and well-dressed Islamists. He chose the Islamists. “Hizb ut-Tahrir gave me that social network and sense of belonging that Britain didn’t - and still doesn’t - offer the young children of immigrants. What are we supposed to sign up for? Identity is a huge problem,” he says.

Although Hizb ut-Tahrir has been accused of attempting to create an environment friendly to violent jihad, a Government report published two years ago advised that it was not involved in violence or terrorism. The US government has also failed to find any links between the group and terrorist activity.

Ed says he finally left the group after a fellow student was killed outside Newham College in east London in 1996. Ayotunde Obanubi was stabbed in a dispute between Muslim and non-Muslim students. Two men were later convicted of his murder. They were said to be followers of Hizb ut-Tahrir, and their conviction led to the National Union of Students banning the organisation from affiliated university and college unions.

Ed’s version of his time in Hizb ut-Tahrir has not gone unchallenged. Hizb ut-Tahrir professes non-violence and has rejected suggestions that Ed was ever a member, describing his reports that he radicalised fellow Muslims as delusions of grandeur.

But Ed is in no doubt that schools are a fertile recruiting ground for militant Islamists, and says it is getting harder for teachers to handle militant pupils.

“I was talking to two RE teachers from Tower Hamlets recently and they tell me these kids are very assertive in saying their non-Muslim teachers are going to hell,” he says.

Fighting terror

Despite warnings that extremists are targeting young Muslims, the Government has so far not seen schools as a priority in the war on terror.

Jonathan Evans, director-general of MI5, said children and teenagers were being groomed to carry out terrorist attacks in Britain.

“Terrorists are methodically and intentionally targeting young people and children in this country,” he said last week, in his first major speech since his appointment in April. “They are radicalising, indoctrinating and grooming young, vulnerable people to carry out acts of terrorism.”

Since September last year, schools in England have a duty to promote community cohesion, but efforts to combat the influence of extremists are concentrated in universities rather than schools.

“Radicalisation of young Muslims is not something we perceive to be a problem at school level, hence we don’t do anything specifically to address it,” says a spokesman for the Department for Children, Schools and Families.

“However, we do promote tolerance, inter-faith work and understanding.”