Police powers adopted to help in the fight against international terrorism may have damaged UK race relations, a key Commons committee was told.
Stop-and-searches on Asian people have hugely increased
The Muslim Council's Sadiq Khan said there was no evidence that stop and search powers had prevented terrorism.
A submission from the Metropolitan Police Authority said officers were making "excessive" use of the powers under S44 of the 2000 Terrorism Act.
The number of Asians stopped was up in London 300% in 2002-3.
Manchester's chief constable Michael Todd meanwhile defended a high-profile anti-terror raid involving the arrest of 10 Kurdish men on suspicion of plotting a terrorist attack, during his evidence to the home affairs committee.
The force had been handed information suggesting the men had tickets for a match at Old Trafford and were planning an attack during a Manchester United game.
Mr Todd said police had no choice but to act on such information - although he added he was furious that details of the football link were leaked to journalists.
All the men were released without charge after only ticket stubs for old matches were found.
Permanently at risk?
The 2000 terrorism act allows police to use special powers within a designated area if there is intelligence suggesting it may be targeted by terrorists.
Section 44 allows police to stop anyone without having particular reason to suspect he or she is about to commit a crime.
The committee heard that effectively the whole of London has been permanently designated as at risk - something which is reviewed every fortnight by Home Secretary David Blunkett and the head of the Metropolitan Police.
Since it came into force stops undertaken under Section 44 in the capital
have risen from 2,830 in 2000-01 to 19,660 in 2003-04.
There have been disproportionate increases in the number of black and Asian people stopped.
The Metropolitan Police Authority said in its submission that it had been given "powerful evidence" that it was having a "hugely negative impact" on community relations.
It added: "Section 44 powers do not appear to have proved an effective weapon against terrorism and may be used for other purposes, despite the explicit limitation expressed in the Act.
"It has increased the level of distrust of our police. It has created deeper racial and ethnic tensions against the police. It has trampled on the basic
human rights of too many Londoners. It has cut off valuable sources of community information and intelligence. It has exacerbated community divisions and weakened social cohesion."
Mr Khan said there was concern the powers were being used in order to tackle wider criminal behaviour rather than terrorism.
"Our concern is that on the ground, police officers are using this power for fishing expeditions."
'Driving while black'
Commenting on the levels of stop and search affecting ethic minorities, Commission for Racial Equality's Trevor Phillips joked: "Back in the 1970s and 1980s, my community were familiar with an offence which we called 'driving while black'."
He added that there was a danger that new offences such as "cruising while Asian" or "driving while under the influence of the Koran".
"The actual target group, Middle Eastern, (white other), and so on are being searched eight times more [than whites] but Asians are being searched five times more than whites for reasons that are not entirely clear."
Last week Home Office figures for England and Wales showed that in 2002/2003 nearly 3,000 Asians were stopped and searched.
The total number of stop and searches under terror laws more than doubled in 2002/2003 from 8,550 to 21,577.