Ken Livingstone lays the wreath

The event marked the 10th anniversary of his death.

Mr Livingstone was accompanied by Stephen's mother Doreen in Eltham, south-east London, where the 18-year-old was stabbed to death by a gang of white men on 22 April, 1993.

No-one has been convicted of the murder.

The Metropolitan Police was accused of "institutional racism" in a report into its investigation of the teenager's death.

Five men were initially arrested but proceedings against two of them were discontinued by the Crown Prosecution Service (CPS).

An inquest into Stephen's death ended in February 1997, with the jury deciding the teenager had been "unlawfully killed in a completely unprovoked racist attack by five white youths".

Suspects acquitted

Stephen's parents, Neville and Doreen Lawrence, then took up a private prosecution against all five but the case against two of them was dropped at the committal stage.

Three men - Neil Acourt, Gary Dobson and Luke Knight - went on trial at the Old Bailey but were formally acquitted in April 1996.

Acourt and David Norris - another of the initial five suspects - were each jailed last year for 18 months for a racist attack on a black police officer.

The sentences were later reduced to 12 months on appeal.

The mayor's visit was part of a day-long visit to south-east London.