Racist groups have directed threatening and abusive letters, pamphlets and cartoons to high-ranking officers, race equality groups and black and Asian organisations after Sir William Macpherson of Cluny's inquiry into the death of the black architecture student.
Scotland Yard has set up a specialist unit of four analysts, which is working alongside the Forensic Science Service to analyse the material and trace those responsible.
Detectives from the Yard's Operation Athena team, which is tackling racial crime, are investigating the activities of a group calling itself "White Lightning" which has been sending hate mail to police and to black groups based in south-east London, close to where Stephen was murdered aged 18 in a racist attack in 1993. The material suggests that he was not killed by a white gang but committed suicide.
One man has been arrested in connection with the White Lightning campaign and further arrests are expected.
The Yard unit, which reports to Deputy Assistant Commissioner John Grieve, head of the Met's Racial and Violent Crimes Task Force, has been given the go-ahead to use scientific techniques normally reserved for murder investigations and for operations aimed at tackling organised crime.
Detective Sergeant David Field, a member of the new unit, has asked people who have received the hate mail not to screw it up but to preserve the material and pass it to the police.
Det Sgt Field said that while some people chose to ignore such literature, others were "shaken to the core". He said: "Race-hate mail takes the abuse into their own home."
Recipients of such correspondence are being urged to treat the material as a "scene of crime". It should be kept within the pages of a magazine and given to police for testing.
He said many of the authors of race-hate mail were individuals, although they sometimes purported to represent larger groups. "They tend to be cranks who write about their own bitterness and their own mixed-up thoughts," he said. However, some of the material is clearly part of a campaign, and is termed a "linked series" by the analysts.
The Met officers are working closely with new racial crime units in the Merseyside, Greater Manchester and South Wales forces to identify the people behind national race-hate mail campaigns.
The Commission for Racial Equality has also been receiving an increase amount of racist mail since publication of the Lawrence inquiry and has compiled a dossier on the material.
The Met is using the intelligence gained by its team of analysts to build up a London-wide database on racists.Reuse content