Stephen Lawrence's mother Doreen set to renew appeal for witnesses on 'Crimewatch'

Doreen Lawrence will appear in an episode of 'Crimewatch' (GETTY)

The mother of Stephen Lawrence is making a renewed televised appeal for fresh witnesses to come forward 20 years after her teenage son was murdered in a racist attack.

In an episode of Crimewatch to be aired tonight, Doreen Lawrence will make a plea for anyone with information about the killing in Eltham, south-east London, to come forward to police.

Following the 20th anniversary of Stephen's death last week, Detective Clive Driscoll will take viewers through the events of the evening of 29 April 1993 when the black student was attacked by a group of six white youths while waiting for a bus.

Following an initial confrontation, Stephen was subsequently stabbed in nearby Dickson Road before the suspects ran away.

Despite securing the convictions of Gary Dobson and David Norris in light of "new and substantial evidence" last year, the case remains open and police believe there may have been witnesses who are yet to make themselves known.

A Scotland Yard spokesman said: "Officers believe there were individuals in the vicinity of the murder who have never come forward." These include two men who got off a bus at the stop opposite from where Stephen was attacked before walking southbound along the east side of Well Hall Road. Investigators would also like to speak to a man who ran from the area of the Well Hall Road roundabout to the bus stop on the same western side of the road as the attack.

Another man was seen walking on the east side of Well Hall Road, south of the roundabout, opposite the Coronet cinema towards the scene of the attack. He was wearing what they call "a very distinctive green jacket with a large 'V'".