Hizb ut-Tahrir: the facts

* Founded in Jerusalem in 1953 with aim of establishing the Caliphate, an Islamic superstate, by revolutionary means

* View on western life: "We should not become integrated into the corrupt western society and accept their diseased notions of democracy, freedom and capitalism"

* Banned in Germany under the country's strict laws against anti-Semitism, and in Russia, and in most of the 40 countries where it operates

* UK arm set up in 1980s by Farid Kassim, Omar Bakri and the Bin Laden-linked Saudi dissident Muhammed al-Masri

* Bakri later broke away to form the more overtly violent al-Muhajiroun

* Now led by a 28-year-old, British-born Indian and IT specialist, Jalaluddin Patel

* Organised in 2002 the largest Muslim conference in the UK, "British or Muslim", which attracted 10,000 people to Wembley Arena

* Three British members were sentenced to five years in jail in Egypt in 2004

* British members have founded the hip-hop group Blakstone and the Muslim lifestyle magazine Salam

* Members work in the education system, the NHS and firms like IBM, Reuters and Tesco