The trial of Nicky Jacobs for the murder of PC Blakelock should never have taken place – it had no chance whatsoever of securing a conviction. This is not because of the passage of time, but because of the paucity and reliability of the evidence.

While many commentators have tried to draw parallels between this case and that of murdered teenager Stephen Lawrence, in that many years have elapsed between the killing and the trial, no such parallels exist. In the Lawrence case evidence existed but police failed to gather it or act on it; in the Jacobs case no such evidence ever existed.

This was a trial in which the state relied heavily on the testimony of three alleged witnesses. However, their testimony contradicted the facts of the case established almost 29 years ago; and they also contradicted each other.

Let's remember that the first two witnesses – given the pseudonyms John Brown and Rhodes Levin to protect their identities – had previously been paid thousands as a "reward" for their help to the Metropolitan police during the first re-investigation in the early 1990s. They were also granted immunity from prosecution, having confessed to being part of the mob that attacked and killed Blakelock and to kicking and punching the officer up to 10 times each.

In 1994 the DPP agreed that the kickers and punchers could receive immunity if testifying against the stabbers and choppers. However in 1985, when the crime occurred, anyone in and around the mob would have been charged with murder under the doctrine of common purpose and joint enterprise.

In July 2013 Levin pleaded guilty to possession of 63 bags of class A drugs with intent to supply. Having already been to prison for drug-related offences, he should have expected a lengthy prison sentence, but because of his role in this trial he received merely a 12-month community service order. He was given relocation costs and at least one plane ticket, to return from holiday in Spain, by the Met. Brown was also given money to pay off his rent arrears and phone bills. The prosecution, and the officers giving testimony in this trial, claimed in court that these were not inducements to encourage their testimony.

But those of us who had been listening in the public gallery find this hard to understand. Especially my friends Winston Silcott and Mark Braithwaite, two of the Tottenham Three who had previously been wrongly convicted and subsequently acquitted of Blakelock's murder. For them this trial felt like deja vu. Not only had it begun in the same courtroom in which they had been wrongfully convicted in March 1987 – court two of the Old Bailey – but the lack of any forensic or scientific evidence to corroborate the testimony, and the reliance on vulnerable individuals to shore up a case built on emotion and desperation, mirrored exactly what happened 27 years ago.

Both Brown and Levin admitted on numerous occasions to having lied to the police. Levin accepted that he had originally named Silcott as the ringleader until after the acquittal in 1991. He then named two other individuals as the "big man" who had led the attack on the officer. He also supplied a further 10 names of members of the mob that he later withdrew, leaving Jacobs as the fall guy. Curiously Brown put the location of the murder at the wrong end of Broadwater Farm. This is interesting because the third witness, "Q", also got the location of the murder totally wrong, but maybe it's not quite as strange as it sounds, as Q is the cousin of Brown. The three "witnesses" each described Jacobs as having a different weapon on the night, Brown said it was a "two-foot scythe," Levin a "six-inch lock blade", and Q a "machete or sharpened piece of scaffold". Levin also admitted to naming others as key players simply because he did not like them. And, alarmingly, Brown told the police in a statement he gave in 1993: "It's very hard for me because … I can't tell the difference between them. To me a black man is a black man."

In court he accepted that this perspective is "pretty much the same today". Nicky Jacobs is a black man.

That the crown has chosen to rely on evidence of this quality to achieve a conviction beggars belief – especially after the embarrassment of the original murder trial that eventually saw all six charged with Blakelock's killing acquitted. This trial had more similarities with an attempted legal lynching then it did with the pursuit for truth and justice.

Those responsible for allowing this trial to take place should now be held to account. This isn't simply about the actions of the police alone; the Crown Prosecution Service must also share responsibility for this debacle. Courtenay Griffiths QC, representing Jacobs, described the decision to charge him as deplorable. But what is even more deplorable is that the family of PC Blakelock has had to endure the agony of yet another trial where the police have sought to make the evidence fit the suspect rather than the other way round.