It all goes back to a spring evening in 1993. Late on 22 April an 18-year-old A-level student called Stephen Lawrence and his friend Duwayne Brooks were making their way home after spending the day together.

The boys were rushing to catch a bus in the south-east London suburb of Eltham - Stephen was already late - when they were confronted by a gang of white youths.

The gang set upon Stephen. A stunned and helpless Duwayne briefly watched in paralysed silence, before he was chased off by one of the white youths.

A campaign portrait of Stephen

Driven by fear and adrenaline, Stephen, managed to scramble free as Duwayne urged him to "just run". But he had been beaten badly and was bleeding profusely.

He collapsed after 200 yards in a pool of blood and died.

What followed - the police investigation, or rather lack of it - sparked the most serious threat to a cohesive urban society since the mass inner-city rioting of 1981.

Britain's Rodney King

The Stephen Lawrence case has been likened to that of Rodney King in America. The acquittal of police officers who were secretly-filmed beating Mr King led to the Los Angeles riots of 1992 which resulted in more than 50 deaths.

The Lawrence public inquiry put the police and British justice as a whole on public trial. It raised allegations of systematic corruption and institutionalised racism.

For many, especially those in the black community, the case held up to ridicule the Rule of Law, a fundamental tenet of any true democracy.

Ironically, on the night of Stephen's killing, the police, in the form of a passing off-duty officer, were at the scene within minutes. But for law-enforcement, that is where the momentum appeared to stop.

Despite receiving numerous tip-offs, within hours of the murder, as to those who might have been responsible for the attack, officers adopted a lacklustre approach to the investigation.

First of many inquiries

Eventually, a senior Scotland Yard officer, Superintendent Roderick Barker, was drafted in to conduct an internal inquiry into the police investigation. He reported that the probe had "progressed satisfactorily and all lines of inquiry had been correctly pursued".

Stephen's parents: Doreen and Neville Lawrence

But as evidence mounted up against the police, both in terms of their handling of the investigation and their treatment of Stephen's parents, Neville and Doreen, it became clear that a more far-reaching investigation would be called for.

A second internal inquiry was ordered by the Police Complaints Authority and conducted by Kent police.

The collapse of the Lawrences' private prosecution began to swell public belief that justice had gone awry. At the inquest into Stephen's death, the five main suspects - Jamie and Neil Acourt, Gary Dobson, Luke Knight and David Norris - refused to answer any questions.

Explosive potential

Newspapers and the wider media started to realise the Lawrence case could become the blue touch paper to an explosive break-up in British race relations.

By the time the Kent force reported back its findings, concluding the police had been well organised and effective, and that there was no evidence of racist conduct, a public inquiry was already in the offing.

In July 1997 the new Home Secretary Jack Straw had announced the inquiry and appointed Sir William Macpherson to chair the hearing.

Evidence from the inquiry kept the Lawrence case in the headlines for much of 1998. Much of the evidence was shocking, including an apology for "our failure" offered by the Metropolitan Police Commissioner Sir Paul Condon to Mr and Mrs Lawrence.

But he has repeatedly denied allegations of institutional racism in his force.