More even than that, the repercussions of Stephen's cruel death rippled through British society showing - through films, plays, music, the media and wider public opinion - a new recognition of the need to re-establish trust between minority ethnic communities and the rest of society.

Few could have thought all that would issue from a mindless attack one quiet April night in Eltham when - as two Appeal Court judges yesterday put it - a "young black man of great promise" was killed "just because of the colour of his skin". That death caused huge disquiet because of the allegations which immediately arose that the authorities bungled the handling of the case because of inherent police racism.

The nation was shocked when Doreen Lawrence, the dead boy's mother, and a special needs teacher, asserted that the officers called to the scene had not tended her dying son because they "did not want to get their hands dirty with a black man's blood". The words electrified British society.

Credence was added to her accusation by the police's apparent focus, not on possible suspects, but on the principal witness Duwayne Brooks, the Lawrence family and Stephen himself. The discrepancy was underlined when we learned that Stephen, trusting and good-natured, had been a model youth whose life was centred around his education and religious faith. Born into a hard-working family who had emigrated from Jamaica in the 1960s, Stephen was doing well - studying A-levels in English, craft, design and technology and physics. He had already been offered a job by a firm of local architects.

The ramifications of his murder continued for almost two decades in a series of twists and turns. In 1996, following the failure of the police to bring anyone to court, Stephen's parents brought a private prosecution against the individuals they suspected of the crime. Unable to get legal aid, the couple relied on donations from the public for what had become a cause célèbre. But the judge ruled that key identification evidence was not admissible, and the jury was directed to acquit.

In 1999 the government announced an inquiry into the police investigation. At its end its chairman, Sir William Macpherson, found that the police had been incompetent, had failed to give first aid at the scene, failed to follow obvious leads in the investigation and failed to arrest obvious suspects.

But more than that it found that there had been a failure of leadership among senior officers who had not implemented recommendations from the 1981 Scarman Report into the 1981 Brixton race riots. Scarman had blamed a few "rotten apples" among police officers. But Macpherson found that the police were "institutionally racist". The phrase polarised the nation.

He made 70 recommendations for reform and also called for other arms of the establishment - including the civil service, local government, the National Health Service, schools, and the judicial system - to root out systemic racism in their own institutions as well.

The repercussions continued. In 2006, the Metropolitan Police Service announced that it would pay Stephen's friend Duwayne Brooks £100,000 as compensation for the manner in which they had treated him after the murder.

Perhaps the most far-reaching recommendation by Macpherson, a retired High Court judge, was that the "double jeopardy" rule should be abolished to allow a suspect to be tried a second time for a crime. The change was enacted in the Criminal Justice Act 2003. Yesterday it was cited by the Court of Appeal, which concluded that "there is sufficient, reliable and substantial evidence to justify the quashing of the acquittal and to order a new trial".

Stephen's parents, Neville and Doreen Lawrence, were at court yesterday to hear the decision. "Perhaps somewhere down the line we will finally get justice for him," Mrs Lawrence said afterwards.

A step has been taken down that road. Two men now stand charged with murder.

Timeline

22 April 1993 Stephen Lawrence is stabbed to death in an unprovoked racist attack.

May-June 1993 Five men are arrested in connection with the murder, including Neil Acourt, Gary Dobson, Luke Knight and David Norris.

29 July 1993 Acourt and Knight are charged, but the case is dropped after the Crown Prosecution Service says there is insufficient evidence.

April 1996 The private prosecution of Acourt, Knight and Dobson collapses after evidence relating to identification of the alleged killers is ruled inadmissible.

10 February 1997 The jury at Stephen Lawrence's inquest returns a verdict of unlawful killing.

July 1997 Home Secretary Jack Straw announces a judicial inquiry.

1 October 1998 Met Police commissioner Sir Paul Condon apologises to the Lawrence family for police failings but denies the force is institutionally racist.

February 1999 The Macpherson Report accuses the police of "institutional racism" and recommends reforms to race relations law.

May 2004 The Crown Prosecution rules out a second attempt at a trial.

July 2006 The police launch the Stephen Lawrence murder review, with 32 officers to re-examining evidence.

February 2009 A report by Dr Richard Stone, a member of the Macperhson inquiry, says the police have made significant progress in reforming, but charges of racism remain.

September 2010 Gary Dobson and David Norris are arrested and charged.

Source Paul Vallely:The Indpendent, Thursday 19th May 2011 http://www.independent.co.uk/opinion/commentators/paul-vallely-a-watershed-moment-for-britain-a-glimmer-of-hope-for-a-family-bereft-2286148.html