Extremist groups can find a ready source of idealistic recruits within universities, according to Anthony Glees. "Mass higher education in Britain offers easy pickings," he says.
Much of the recruitment is done by radical student societies that provide strong peer group support to nurture radical mindsets. While most do not advocate violence, some individuals, exposed to more hardcore doctrine may "graduate" to violence.
Setting up student societies is straightforward and, according to Glees, they provide a useful cover. There is little or no monitoring of their activities by student unions or the university authorities, while the police Special Branch only occasionally casts an eye over freshers' fairs.
The National Union of Students has banned organisations that it feels incite violence from operating on campus.
Some respond by simply adopting a new name; others are more naive. A student union official told Glees that in 2004, students attempted to set up an "official al-Qaeda society" to "discuss topical events". The request was denied.
* Al-Muhajiroun , recently proscribed by the Government, has long been banned by the NUS. But its leader, Omar Bakri Mohammed, boasts that it slips onto campuses as "the Pakistani Society" or "the Bangladeshi Society". It has also been called "the Saved Sect". While the group says it is not engaged in military activity and is a "purely ideological organisation", some analysts see it as a radicalising agent that turns young British Muslims against Britain.
* Hizb ut-Tahrir is an anti-Hindu, anti-Sikh, homophobic, anti-feminist group that is resentful of the West's influence on Islam. It has issued anti-Semitic statements.
The organisation denounced the July 7 bombings and claims to promote non-violent debate, but its 2003 conference concluded that Muslims could not be British. In August, the Government announced that it would be banned.
Despite an NUS proscription, Hizb ut-Tahrir's influence has been reported at Kingston, Birmingham and Leicester universities and at Imperial College London, which hosted the group's first UK website.
* The Muslim Public Affairs Committee UK can be extreme but does not advocate violence against the state. MPACUK is banned by the NUS due to incidents of homophobia, anti-Hinduism and anti-Semitism. It urges Muslims to take an active part in politics and to debate the issues that affect them.