Secret video footage reveals Muslim preachers exhorting followers to prepare for jihad, to hit girls for not wearing the hijab, and to create a 'state within a state'. Many of the preachers are linked to the Wahhabi strain of Islam practised in Saudi Arabia, which funds a number of Britain's leading Islamic institutions.

At the Sparkbrook mosque, run by UK Islamic Mission (UKIM), an organisation that maintains 45 mosques in Britain and which Tony Blair has said 'is extremely valued by the government for its multi-faith and multicultural activities', a preacher is captured on film praising the Taliban. In response to the news that a British Muslim solider was killed fighting the Taliban, the speaker declares: 'The hero of Islam is the one who separated his head from his shoulders.'

Another speaker says Muslims cannot accept the rule of non-Muslims. 'You cannot accept the rule of the kaffir [non-Muslim],' a preacher, Dr Ijaz Mian, tells a meeting held within the mosque. 'We have to rule ourselves and we have to rule the others.'

Elsewhere the documentary records the huge popularity of DVDs and internet broadcasts produced by extremist preachers. At the Islamic bookstore at Regent's Park Mosque in central London, DVDs of a preacher called Sheikh Yasin are sold. In one DVD, Yasin, who is promoted on the mosque's website, accuses missionaries from the World Health Organisation and Christian groups of putting the 'Aids virus' in the medicine of African people, 'which is a conspiracy'.