A Dispatches reporter attends mosques run by organisations whose public faces are presented as moderate and finds preachers condemning integration into British society, condemning democracy and praising the Taliban for killing British soldiers…

Dispatches has investigated a number of mosques run by high profile national organisations that claim to be dedicated to moderation and dialogue with other faiths. But an undercover reporter joined worshippers to find a message of religious bigotry and extremism being preached.

He captures chilling sermons in which Saudi-trained preachers proclaim the supremacy of Islam, preach hatred for non-Muslims and for Muslims who do not follow their extreme beliefs - and predict a coming jihad. "An army of Muslims will arise," announces one preacher. Another preacher said British Muslims must "dismantle" British democracy - they must "live like a state within a state" until they are "strong enough to take over."

The investigation reveals Saudi Arabian universities are recruiting young Western Muslims to train them in their extreme theology, then sending them back to the West to spread the word. And the Dispatches reporter discovers that British Muslims can ask for fatwas, religious rulings, direct from the top religious leader in Saudi Arabia, the Grand Mufti.

Saudi-trained preachers are also promoted in DVDs and books on sale at religious centres and sermons broadcast on websites. These publications and webcasts disseminate beliefs about women such as: "Allah has created the woman deficient, her intellect is incomplete", and girls: "By the age of 10 if she doesn’t wear hijab, we hit her," and there’s an extreme hostility towards homosexuals.

Almost half of Britain’s mosques are under the control of a hardline Islamic sect whose leading preacher loathes Western values and has called on Muslims to “shed blood” for Allah, an investigation by The Times has found.

Riyadh ul Haq, who supports armed jihad and preaches contempt for Jews, Christians and Hindus, is in line to become the spiritual leader of the Deobandi sect in Britain. The ultra-conservative movement, which gave birth to the Taleban in Afghanistan, now runs more than 600 of Britain’s 1,350 mosques, according to a police report seen by The Times.

Seventeen of Britain’s 26 Islamic seminaries are run by Deobandis and they produce 80 per cent of home-trained Muslim clerics. Many had their studies funded by local education authority grants. The sect, which has significant representation on the Muslim Council of Britain, is at its strongest in the towns and cities of the Midlands and northern England.

Figures supplied to The Times by the Lancashire Council of Mosques reveal that 59 of the 75 mosques in five towns – Blackburn, Bolton, Preston, Oldham and Burnley – are Deobandi-run.

A commentator on religious radicalism in Pakistan, where Deobandis wield significant political influence, told The Times that “blind ignorance” on the part of the Government in Britain had allowed the Deobandis to become the dominant voice of Islam in Britain’s mosques.

Khaled Ahmed said: “The UK has been ruined by the puritanism of the Deobandis. You’ve allowed the takeover of the mosques. You can’t run multiculturalism like that, because that’s a way of destroying yourself. In Britain, the Deobandi message has become even more extreme than it is in Pakistan. It’s mind-boggling.”