Prosecutor Mark Ellis told the court that the evidence he is going to present centres around textile fibres, blood and hair on the defendants’ clothing, seized by police in 1993.

However, the defence has claimed that evidence was accidentally transferred to the defendants’ clothes during handling by police and scientists. Timothy Roberts QC, who is defending, said: “The physical evidence on which this charge is based… won’t fill a teaspoon.”

Stephen Lawrence was murdered in 1993 when he was just 18. It is believed that the attack on the black teenager by a gang of white youths was racially motivated.

Gary Dobson, 36, and David Norris, 35, stand accused of the killing some 18 years after it took place.

The murder is one of Britain’s most infamous cold cases, after an inquiry into the Metropolitan Police’s handling of it concluded that the force was “institutionally racist”.

Both Dobson and Norris were initially arrested within days of the murder, but were never convicted. However, a cold case review by police in 2007 revealed the DNA findings, owing to a fresh approach by forensic scientists.

The prosecution has admitted that it cannot prove whether either of the men held the knife that killed Stephen Lawrence, but contends that they were part of a group of “like-minded” men who acted together in a “totally unprovoked” attack.

Ellison added: “The only discernible reason [for the attack] was the colour of his skin.”