The move came on an emotional day in the anti-racist calendar. A march commemorated the 20th anniversary of the death of Blair Peach, who died as police intervened in an anti-Nazi demonstration in Southall, west London, while in Worcester police prevented a National Front march from taking place.
In Brixton, police hoped the reconstruction, which began around 5.30pm, the time of last Saturday's explosion, would provide them with more clues about the identity of the bomber, whom they now believe was racially motivated. Four racist groups have so far claimed responsibility, including the neo- Nazi Combat 18, which is thought to have made the claim from a phone box in Well Hall Road, Eltham, where Stephen Lawrence was murdered.
One of the key aims of the reconstruction was to speak to passengers on a bus which broke down on its way to Streatham at the time of the blast. Detectives, who have yet to make any arrests, suspect the bomber did not intend the bomb to explode in Brixton and may have been travelling on the bus to lay the device elsewhere.
Anti-Nazi League demonstrators held a protest to coincide with the Brixton reconstruction despite criticism from local community groups worried the march would interfere with the police investigation. Meanwhile, the area remained typically busy for a Saturday afternoon, with no sign that the explosion had deterred shoppers.
Commander Hugh Orde, Metropolitan Police head of crime for south-west London, said he was aware of tension that may prevent black witnesses from speaking to police and that third parties would mediate between witnesses and officers. "We have to convince them in this case that if this bomb went off in Downing Street, not even one more police officer would be investigating it," he said. "We must recognise our recent history and do everything we can to capture that vital lead."
Meanwhile, 10 miles away in west London, 500 campaigners marched past the spot where anti-racism demonstrator Blair Peach died, in commemoration of the 20th anniversary of his death. Mr Peach, a special needs teacher, was allegedly killed by a blow to the head as police tried to disperse demonstrators protesting against a rally in Southall, the heart of London's Indian community, by the far-right National Front.
Eleven witnesses reported seeing Mr Peach struck by police. Willie Whitelaw, then Conservative home secretary, resisted demands for a public inquiry into the death while the report of an internal Metropolitan Police investigation by Commander John Cass has never been released.
Although the Metropolitan Police reached an out-of-court settlement with Mr Peach's brother in 1989, no officer has ever been charged in connection with his death. Mr Peach's former partner, Celia Stubbs, has appealed to Home Secretary Jack Straw - one of 79 MPs who called for a public inquiry into the incident at the time - to make public a copy of the Cass report.
In a third event in an intense weekend for race relations, a planned march by the National Front in Worcester was called off after police refused permission for it to go ahead. A counter-protest by a group of anti-Nazi demonstrators passed off peacefully. Alan Peach, a spokesman for West Mercia Police, said his force was surprised the NF had applied to march in Worcester. "We do have ethnic groups living in the city," he said, "but they live in harmony with the rest of the community and there have been no problems."