The report, detailed in a Sunday newspaper three days before its official release, criticises the force's commissioner, Sir Paul Condon, for his handling of the investigation into Stephen Lawrence's death.

Sir William Macpherson's inquiry into the 1993 murder of the black teenager concludes that London's police service is riven by a "pernicious and institutionalised racism".

Des Parkinson reacts to the Lawrence findings

But as the Metropolitan Police braces itself to face further anger, a group of senior police officers has rejected the racism accusations.

Chief Superintendent Des Parkinson, National Secretary of the Police Superintendents' Association for England and Wales, said he was "amazed" by them.

BBC Community Affairs Corresondent Reeta Chakrabarti: The Lawrence family 'upset' by leaked details

"We don't believe that there is institutionalised racism in the Metropolitan Police force or in the police service in general," he said.

"We accept that some things that took place in the Lawrence inquiry weren't nearly as good as they should have been."

He told BBC Radio 5 Live: "It would be very sad if Sir Paul went in these circumstances and we want him to stay."

But Peter Herbert, Chairman of the Society of Black Lawyers, said: "The findings of pernicious institutionalised racism are long overdue.

"If these recommendations are right, then Sir William Macpherson and his colleagues have seized the moment.

"I think these recommendations would be a milestone in race relations in Britain."

Extracts of the report entered the public domain after the relaxing of an injunction that banned its publication before Wednesday's release in the Commons.

Damian Grammaticus assesses race relations and policing in Birmingham

The Home Office has received fierce criticism from the Conservatives for blocking the Sunday Telegraph's later editions. Both the Tories and the Telegraph have accused the government of manipulating the media.

The government is to launch an inquiry to find the source of the leak. It is understood fewer than 10 copies were delivered to ministers.

The Lawrence family have asked to see a copy immediately so they can have their reaction ready for its official release.

'Acceptance of problems'

The inquiry report says: "There must be an unequivocal acceptance of the problems of institutionalised racism."

It adds: "Any chief police officer who feels unable to so respond will find it extremely difficult to work in harmony and co-operate with the community in the way that policing by consent demands."

Sir Paul is likely to face fierce criticism if he rejects the report's findings, though they are not believed to call on him to resign.

He has always rejected accusations of institutional racism in his force, although other police chiefs, including Greater Manchester Police Chief Constable David Wilmot, have acknowledged "internalised" racism.

The BBC's Mike Thompson gauges reaction on the streets of multi-cultural Brixton in south London

It is thought Home Secretary Jack Straw wants Sir Paul to stay in his post until he is due to take retirement in January next year.

The Sunday Telegraph said Sir Paul was expected to put his job at the disposal of Mr Straw, an allegation denied by a Scotland Yard spokesman.

"His position is our official position - which is that neither he nor the Metropolitan Police have seen the report and we feel it is inappropriate to comment until it is laid before Parliament," he said.

Stephen Lawrence: Murder unsolved

The report is also said to attack him over a "lack of rigour" in his reaction to an earlier internal inquiry, which gave the police investigations a clean bill of health.

John Stalker, the former Deputy Chief Constable of Manchester police, said Sir Paul "must resign - his position is untenable".

Writing in The Mirror, he said the Lawrence report "is so sweepingly condemnatory of racism within his force he must take ultimate responsibility and go".

The Sunday Telegraph says the report contains 70 recommendations "designed to usher in a fundamental transformation of Britain's race relations".

These include recommendations on how to change the legal and criminal justice system.

The newspaper says a key proposal is to give the Court of Appeal power to allow prosecutions after an earlier acquittal when fresh evidence is produced.