Stephen Lawrence was murdered in April 1993

However, he maintained there was still more evidence to present to the CPS, saying: "We haven't finished the work that we're doing."

"The people who murdered Stephen need to be brought to justice."

Neil Acourt, Gary Dobson and Luke Knight were tried at the Old Bailey for the murder but were formally acquitted in April 1996.

The judge ruled that identification evidence from Duwayne Brooks, a friend of Stephen, was inadmissible.

The case against two other men had been discontinued.

The case led to proposals to end the double jeopardy rule which prevents suspects being tried twice for the same crime.

Investigation

Mr Grieve is the head of London's police unit investigating race-hate crimes and is a former head of Britain's anti-terrorist branch.

Stephen Lawrence murder

April 1993 Stephen stabbed to death July 1993 Charges against Jamie Acourt and David Norris dropped April 1996 Private prosecution against Neil Acourt, Gary Dobson and Luke Knight collapses 1998 Inquiry into the murder February 1999 Sir William Macpherson makes 70 recommendations to end institutionalised racism

He said the real milestone for Stephen's parents would come when prosecutions could be bought "against anybody, whether they're people you've heard about or whether it's anybody else."

Mr Grieve also went on to talk about the problems of policing what he called the "patchwork quilt that is London's communities".

"I think you have to be careful about the extremists at one extreme, but be careful not to switch off those who can help you, those who can provide you with support," he added.

London was probably the most "diverse city on this planet" with over 10,000 calls made to the Metropolitan Police service every day, he said.

However this diversity called for a "massive amount of interaction" with different ethnic communities.

Tribute

Mr Grieve also spoke out about the impact the Stephen Lawrence murder inquiry had on the Metropolitan Police's handling of race-hate crimes.

"We're arresting 200 people a month and we're getting 300 clear ups for hate crimes across London, " he said.

"That is a tribute to Mr and Mrs Lawrence and the Stephen Lawrence inquiry."

"I can't remember a single solitary day that we didn't work to our utmost to make people we are working for feel safe," he added.