Prime Minister Tony Blair recently described tolerance as ‘what makes Britain Britain’ but in this extensive investigation Dispatches reveals how a message of hatred and segregation is being spread throughout the UK and examines how it is influenced by the religious establishment of Saudi Arabia.

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.