The BBC's Robin Denselow: "The quite extraordinary repercussions of Stephen's death continue"

Kent Police spoke for the first time on BBC Two's Newsnight on Friday about vital witnesses who were missed and key leads that have still not been followed up by Scotland Yard's "seriously flawed" investigation into the stabbing.

Speaking on the programme, Deputy Chief Constable Bob Ayling, who headed the Kent team with Detective Chief Superintendent David Clapperton, described the murder investigation as "the effort of a B team ... not the best that the Metropolitan Police could have provided".

The Kent probe into the investigation of Stephen's murder on 22 April 1993 in Eltham, south east London, was carried out after a complaint to the Police Complaints Authority by Stephen Lawrence's parents.

The suspects: Case against them collapsed

The investigation found that one of the most important witnesses - known as James Grant - came forward after a televised appeal, but was seen by nobody more senior than a detective sergeant and his statement was basically dismissed.

His information pertained to "Witness K" who had been at the house of two brothers, Neil and Jamie Acourt, on the night of Stephen's murder.

Reeta Chakrabarti reports on the comments of Kent Police

The Acourts were later tried but not convicted in 1996 for the murder, along with Gary Dobson, Luke Knight and David Norris.

Mr Clapperton said Witness K reportedly saw the Acourts "in a state of undress and they had been washing themselves and perhaps articles" when he told them about the murder.

Anonymous notes: Named the Acourts

"They reacted quite significantly. They were surprised and appeared to be quite disturbed," he said.

It was "quite clear" that Witness K believed the Acourts were involved in the murder, but he has only ever provided a short statement to police and has never been involved in any "criminal proceedings".

He is now understood to be too terrified to give evidence.

Mr Clapperton suggested that "very little" was done to follow up other vital witnesses or evidence, including three phonecalls from a female with information that could "only have come from someone very close to those who committed the murder".

'Blonde attacker'

In addition, Duwayne Brooks, a friend who was with Stephen when he was stabbed, maintains the attacker had blonde or fair hair, which none of the five suspects are known to have had.

The Lawrence suspects: Playing with knives and making racist comments

Mr Clapperton said: "I think it's very significant. What the police inquiry needs to do is establish which of the prime suspects had fair hair ... and if none of them had fair hair, is there an unknown suspect offender out there who's never been spoken to?"

He added that there was "speculation" that to join the Acourts gang "you had to stab someone ... maybe, just maybe, this was a new member of the gang who wanted to show their worth by stabbing Stephen".

Kent Police also found that an "anonymous male" had sent a series of notes to police and made phonecalls concerning the killing.

One of the notes said that the Acourts were "very dangerous knife-users who always carry knives and quite like using them".

It linked them to another stabbing and tallied closely with evidence from a police surveillance video that showed the suspects making racist comments and playing with knives.

In an effort to challenge all previous assumptions of the case, the Kent investigation also re-examined the roles of all the prime suspects and concluded that Gary Dobson was probably involved to a lesser extent and "in a different category to the other four".

The Kent Police probe provided much of the material for what are expected to be the highly damning findings of the public inquiry into the Lawrence case.