The assistant commissioner of the Metropolitan Police Service says the force “will not give up" on bringing Keith Blakelock’s killers to justice.
Assistant Commissioner Mark Rowley promised to continue the fight to make sure PC Blakelock’s attacker face the full extent of the law, almost three decades after the murder.
The statement was made after a jury today cleared Nicky Jacobs, 45, of killing PC Blakelock following a six-week trial at the Old Bailey.
The officer was attacked by an armed mob after his unit was deployed to protect firefighters tackling a blaze during the 1985 Broadwater Farm Riots, in Tottenham, in October 1985.
Jacobs, who was 16 at the time, was accused of being one of the rioters who together stabbed the officer more than 40 times and tried to decapitate him.
Mr Rowley said: "PC Keith Blakelock joined the Met Police to serve and protect the community of London.
“That desire ended in his murder, following an attack that was without mercy, his murder was barbaric.
"That terrible night in October 1985 Keith, and his colleagues of Serial 502, were sent to the Broadwater Farm Estate to protect fire crews battling to control a blaze that was threatening to take hold of a block of flats.
“Keith was only present that night to do what he joined to do - protect and serve the community of Tottenham.
"Today, having considered all the evidence they were asked to, the jury have concluded that Nicholas Jacobs is not guilty.”
The assistant commissioner said the Met had worked closely with the Crown Prosecution Service over many years to be in a position to put evidence before a court.
He added: “The investigation team pursued all the material, evidence and witnesses they could.
“No matter how difficult an investigation it has been to carry out - given the many years that have passed, the lack of forensic evidence and CCTV plus the main witnesses to Keith murder's being those taking part in the riot - it was important we exhausted every possible lead we could.
"Sadly, Keith's widow, family and friends still have not seen anyone brought to justice for his murder. The dignity, extraordinary patience and courage they have shown in their nearly thirty year quest for justice is humbling."
He added: "We will not give up on bringing Keith's killers to justice.
“There are people who know exactly who took part in the attack on Keith and people who took part themselves.
“It is not too late for you to come forward. Almost thirty years on peoples' lives are very different, their allegiances broken or shifted. Help us now.
"October 6, 1985 was an extremely sad day in the history of policing, and no police officer serving at that time will ever forget it.
“Today everyone in the police family should reflect on the barbaric and tragic events Keith, and Serial 502, experienced that night."
Jacobs, who had denied murder, was the seventh person to be tried for the Blakelock killing.
The jury, which also cleared Jacobs of manslaughter, cleared him of murder after deliberating for six hours and 15 minutes.
Jacobs was charged last year after a multi-million pound reinvestigation by Scotland Yard.
Jenny Hopkins, deputy chief crown prosecutor for CPS London, said the trial was fair and the service must respect the jury’s decision.
She said the CPS had reviewed material from three police investigations spanning more than 20 years and concluded there was sufficient evidence for a realistic prospect of conviction and that it was in the public interest to charge Nicholas Jacobs.
She added the evidence included three witnesses who the prosecution said gave their accounts independently, with no suggestion of collusion.
Ms Hopkins said before the start of the trial the defence made an application to stop the proceedings, arguing that the defendant could not have a fair trial due to a number of reasons, including the delay of 28 years since the murder.
This application was unsuccessful and the judge ruled that Jacobs could have a fair trial.
Ms Hopkins added: “At the close of the prosecution case the defence argued that there was no case to answer, however, the judge ruled that there was a case to answer and it was for the jury to decide on the guilt of the defendant.
“It was right that all the evidence in this case was put before a jury and we respect its decision.”