Less than 4 per cent of the people arrested under anti-terror laws since the September 11 attacks five years ago have been convicted of terrorist offences, it was disclosed yesterday.

Following warnings from Muslim groups over the growing alienation of large sections of the community, the Government faced demands for an overhaul of anti-terrorist legislation.

Ministers also came under sustained fire in the House of Lords for their use of control orders against terrorist suspects, with peers warning that the policy could backfire by attracting support for extremism.

Statistics released by the Home Office disclosed that 1,166 people were detained between 11 September 2001, and 31 December last year on suspicion of involvement in terrorism.

These arrests have so far led to 221 charges and just 40 convictions, although some other prosecutions are still in the pipeline.

Massoud Shadjareh, chairman of the Islamic Human Rights Commission, said that families had been destroyed, children traumatised and innocent people criminalised as a result of the legislation. "These are not just empty statistics but innocent human beings whose lives have been shattered by such heavy-handed and discriminatory policies," he said.