Scotland Yard was left humiliated again today when the evidence of one of its most important supergrasses of the past decade was rejected by an Old Bailey judge.
It follows the collapse earlier this year of the £30 million investigation into the 1987 murder of private eye Daniel Morgan.
Then no evidence was offered against the alleged killers after three star witnesses, including Michael Eaton, were found to be totally unreliable.
Now a second trial based on Eaton's allegations that Mandy Fleming had hired a hitman to kill her rich husband in 2004 has also been dropped.
Fleming did admit drilling holes in Adam Fleming's £90,000 luxury cruiser which sank in Brighton marina on Valentine's Day 2004. But In both cases the trial judge ruled that Eaton - described as a pathological liar with a history of psychiatric illness - was incapable of being believed.
A total of seven people have now walked free of murder charges after Eaton was proved to be a worthless witness.
Yet in 2008 Eaton had been rewarded for giving evidence in these trials with 25 years being cut from the prison sentence he would have received for his own crimes - and has since been released.
In a judgement which can be revealed for the first time today, Judge Richard Hone condemned Eaton as "not just unreliable but false and highly dangerous."
"Eaton is capable of inventing detailed accounts of events which never happened and shows either blatant untruthfulness or alternatively a component of his personality disorder typified by folie de grandeur and self aggrandisment," he said in a withering 12 page judgment.
"By the time the summing up of Eaton's evidence of unreliability, fabrication and fantasy had concluded it would be impossible to find a sufficient bedrock of truth upon which a jury could convict any of the defendants."
Eaton, who also called himself Gary Smith, has been convicted of 30 offences, including thieving from a blind woman, and violence to his ex-partner Christine Kirby.
"It is evident that he has pride in a reputation for being a violent person," said Judge Hone. In 2008 he pleaded guilty to 20 offences - and asked for 32 more to be taken into consideration - including conspiracy to murder, bribing police officers, blackmail, firearms, burglaries and cocaine dealing.
At the Old Bailey, Judge Gerald Gordon described the case as unique and reduced a 28-year sentence to just three years because he had agreed to give evidence in the other trials.
Eaton's barrister Sarah Forshaw QC said he had put his life on the line to "clear his conscience."
"He had nothing to gain and everything to lose," she told the court. But when his evidence was produced in court psychiatrist Prof Nigel Eastman said Eaton had spent a long time in mental health care and had a personality disorder.
He described Eaton's "pointless lies... deviousness... unsubstantiated claims" and his ability "to lie well beyond an ordinary person."
He once told so many people that his mother had died that he persuaded them to contribute to her funeral. In fact she was alive and well and he was visiting her regularly.
In the Fleming case Eaton's statements were so full of lies he called called her Denise and not Mandy and mistook the address of his alleged target whom he thought was Irish when he was from the east end of London.
He also repeatedly changed his mind over the make of gun he had bought to carry out the hit and even the size of the contract he would have earned.
He claimed at one stage that he was at the heart of the conspiracy at a time when he was an in patient at a pscychiatric hosptial.
Finally he claimed he called the whole shooting off after he had sat in a Mitcham pub with Mr Fleming and found out he was "a nice chap."
Today Judge Hone ruled that charges against Mandy Fleming, 57 of Sheerness, and her then lover David Brown 50 of Sherness who had all denied conspiring with Gary Eaton to murder Adam Fleming between January 2004 and June 2006 should lie on the file.
Prosecutors offered no evidence on the same charge against Bradley Hanson, 27, of Littlehampton, W Sussex.
Mandy Fleming pleaded guilty to damaging her husband's Double Dragon luxury cruiser being reckless as to whether life would be endangered. She will be sentenced on this charge next month.
No evidence was also offered against David Camp, 67 of Shirley, Croydon, who had denied selling a prohibited weapon, a 9mm semi-automatic pistol, to Eaton between October 2004 and July 2006.
Adam Fleming, 45 of Mitcham, has started a civil action in the High Court claiming £55,000 for damage to his boat from his ex wife. The couple had met in Wales in the mid-1990s and were married on Turtle Bay Beach, Florida in 2002.
But after she started her affair with Mr Brown Mr Fleming sued for divorce which was finalised in July 2005. Fleming and Brown have since split up.
No one has been brought to justice for the Morgan murder 24 years ago. the victim was killed when hatchet was buried in his head in the car park of the Golden Lion in Sydenham.