The discrediting of an unqualified "expert" - found to have cut-and-pasted the same evidence for several different cases - has led to the collapse of a multi-million pound fraud trial.
Andrew Ager had been hired by the prosecution team in a trial of eight men accused of a £7m carbon credit fraud at Southwark Crown Court.
But Judge Nicholas Loraine-Smith was alerted to the fact that Mr Ager did not have any relevant qualifications.
He ruled the men should be cleared.
In closing the case, the judge said: "Andrew Ager is not an expert of suitable calibre. He had little or no understanding of the duties of an expert. He had received no training and attended no courses. He has no academic qualifications. His work has never been peer-reviewed."
There are significant implications as Mr Ager has appeared for the prosecution in at least 20 other cases - and the Metropolitan Police is now referring the matter to the National Crime Agency.
Lawyers estimate the current trial, which heard evidence for three weeks before it was halted, has cost millions in public money.
The prosecution alleged that from 2011 to 2018 the eight men - Steven Sulley, Ashley Hunte, David Pierce, Christopher Woolcott, Christopher Chapman, Marcus Allen, Daniel Martin and Lewis Deakin - were engaged in fraud directly or engaged in laundering the proceeds of fraud.
The fraud, it was alleged, was perpetrated on members of the public, who were persuaded to make investments, including in the purchase of carbon credits.
Carbon credits are a global scheme aimed at reducing the amount of greenhouse gases released into the atmosphere.
The credit itself is best described as a permit that can be purchased by a company so that it can emit a certain amount of carbon dioxide on the understanding that any damage to the environment is being offset by another company elsewhere in the world.
There is a market in trading carbon credits but it is not really accessible to small investors and, because of the way the system is administered, it is unlikely that larger investors could expect to make much of a return.
Mr Ager's role in the prosecution was to make the case that the defendants must have known they were asking investors to buy a product that could not be sold on and was effectively worthless.
The prosecution case relied on Mr Ager's evidence - supplied in the form of a written statement to the court - making the point to the jury that anyone, with any knowledge of the market, would have been fully aware how little prospect there was of being able to make any profit.
That would enable the prosecutors to prove that the defendants knew they were committing a fraud.
'Ferraris and Lamborghinis'
But the court was told that Mr Ager had made a telephone call to Marius-Cristian Frunza, an expert in financial crime and risk management, who was giving evidence in support of one of the defendants - in an attempt to dissuade him from giving his own evidence.
In that phone call, just two weeks before the trial started, Mr Ager made a number of claims, including that several people had died as a result of losing their money - but the court heard there was no evidence of that.
He also told Dr Frunza that a police report had revealed that the defendants had spent money on Ferraris, Lamborghinis and Aston Martins - but again there was no such report.
The judge said Mr Ager had attempted to convince Dr Frunza that, if he spoke in court, he risked being in a "horrendous environment" in which he he would find out "what you are defending is someone who has taken someone's life savings".
But the judge said there was a clear reason why Mr Ager wanted to keep Dr Frunza from giving evidence.
"Mr Ager was keen that his evidence should not be challenged and he felt threatened by the prospect of a far more impressive expert appearing in an area of expertise in which he hoped to continue making a living."
'Cupboard under stairs'
After it became known he had made the phone call, Mr Ager was subsequently cross-examined in court and revealed that he did not have a degree and "couldn't remember" if he had passed any A-levels.
And despite his assertion that he was fully-informed about the carbon credits market, he admitted that he had not read any books on the subject, not even the one that had been written by Dr Frunza.
He also admitted that he had made no notes of his workings and that he had kept sensitive material provided by the police in a cupboard under the stairs and this had been damaged by a "leak".
It also emerged, during the trial, that Mr Ager's witness statements had been "cut-and-pasted" - albeit with the names changed - from documents he had supplied to other trials.
'Disclosure is a cornerstone'
On the handling of evidence, Judge Loraine-Smith described the disclosure in the case as "pretty chaotic and unsatisfactory".
Narita Bahra QC, the defence counsel for Steven Sulley, told the BBC that "this case is an illustration that disclosure failings are not limited to sexual offence cases" and added: "Drastic action needs to be taken by the Crown Prosecution Service to manage the police and disclosure process. The onus should not be on a defence team to uncover a miscarriage of justice."
A City of London Police statement said: "Together with our colleagues in the CPS, we apologise that the evidential and procedural issues in the case have led to its dismissal.
"Regrettably we haven't been able to provide these victims with the level of service we continually strive for and for that we sincerely apologise."
Disclosure is the process whereby police and prosecutors must disclose to the defence any evidence gathered by police which either assists the defence case or undermines the prosecution.
It is a cornerstone of a fair trial system, and came under intense scrutiny in late 2017 when a series of disclosure failures in high profile rape cases led to trials collapsing, most notably that of Liam Allen who was cleared of rape.
The defence team for Mr Sulley lodged a complaint with the Metropolitan Police about Mr Ager.
The Met have indicated that due to the complexity of the case they will be referring the matter to the National Crime Agency for investigation.
The judge said that only one of the investors, many of whom were elderly, had succeeded in getting their money back. "Those investors deserved a full and proper investigation of those allegations, and they have been badly let down."