Speakers for the Hizb ut-Tahrir Party, which says that it is non-violent but is banned in several European countries, said that the crackdown on extremist activity would anger Muslims in Britain.

The group has condemned the suicide bombings in London and urged Muslims to be “decent citizens” under Islamic law and to co-operate with police investigations.

However, Tony Blair was accused of “lies, lies and damned lies” by Muslim leaders who claimed that he was silencing legitimate political expression while befriending Muslim dictators who oppress their people.

The conference, at the Royal National Hotel, in Bloomsbury, was told that Muslims in Britain were living in fear of harassment, arrest and execution after the shooting of an innocent Brazilian man on the Tube. It was said there were fears that Islamic blood had become legal to spill on the streets of London.

A senior member of the party, Abdul Waheed, told the delegates to speak out against British and American foreign policy. “Foreign policy anger is there. There is an attempt here to silence Muslims,” he said.

“Go back to your communities and go to your mosques and ask the leaders do they not think there is going to be more frustration in the Muslim community, young and old alike, if the mosques cannot be used to discuss these issues in a calm and rational way.

“If we are not allowed to discuss the actions in Iraq and Afghanistan . . . I fear the frustration builds up more, not less.”

Dr Waheed urged Muslims to be “steadfast and brave” and said: “After your hardship there follows ease.” Muslims were told to reject calls for them to “defeat the extremists” and were told to stand united on the path to establishing a true state of Islam.

Imran Waheed, the spokesman for Hizb ut-Tahrir in Britain, said the Muslim community had been blamed for the July 7 bombings and that police activity had left the community feeling stigmatised. “If a non-Muslim, innocent electrician can be killed on a mere hunch . . . what fate awaits Muslims if a man with a beard runs on to a Tube with a rucksack?” he asked.

The party campaigns for a government based on Islamic Sharia across the Muslim world but says that this would not be an oppressive regime such as the Taleban.

In Lincolnshire this weekend a Muslim festival attracted more than 4,000 people to hear speakers and pray. Organised by the Islamic Society of Britain, the annual gathering promises a family day out and peaceful lectures but there are reports of a radical tendency among the youth of the society.

Young Muslims have been found to promote jihad on its website calling it “to be a soldier for Allah, devoting your very soul and everything you own to Him”.

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