A retrial of eight former policemen cleared of manufacturing an investigation which led to the wrongful conviction of three men would be "highly unlikely", a legal expert has said.
The retired officers were acquitted of perjury last year after a judge heard that key documents in the case had been mistakenly shredded. The absence of the files meant the defendants would not get a fair trial, it was said.
However, the Independent Police Complaints Commission (IPCC) revealed on Thursday that the papers had not been destroyed, but had simply gone missing. The aborted trial - into the 1988 murder of Lynette White - was estimated to have cost the taxpayer £30 million and is thought to be the most expensive case of its kind in British legal history.
Winston Roddick QC said that while it is theoretically possible to start a new trial, he did not believe it was a likely scenario. Mr Roddick, who was first called to the Bar in 1968, said: "What we are dealing with is an acquittal by jury on the decision of the judge.
"This was made because the judge came to the view the defence could not continue to get a fair trial, due to these 'destroyed' documents. Under the Criminal Justice Act 2003, a conviction can be quashed via the Court of Appeal when new and compelling evidence arises.
"This new evidence would have to favour the prosecution's case in order for an acquittal to be quashed. However, from what I understand, the documents at the centre of this matter did not favour the prosecution - but the defence. A retrial, therefore, would be highly unlikely."
The officers - Graham Mouncher, Thomas Page, Richard Powell, John Seaford, Michael Daniels, Peter Greenwood, Paul Jennings and Paul Stephen - were involved in the original investigation of the murder of Ms White.
Tony Paris, Yusef Abdullahi and Stephen Miller - who became known as the Cardiff Three - were wrongly jailed for life in 1990 for the murder. They were freed in 1992 after their convictions were quashed.
The case was reopened in September 2000 when new evidence was brought to light. Advances in DNA led to the arrest of security guard Jeffrey Gafoor, who was jailed for life for the murder in July 2003.
In 2005, the former police officers were arrested and questioned on suspicion of false imprisonment, conspiracy to pervert the course of justice and misconduct in public office.It was alleged they had "manufactured" the case after the murder at a flat in Cardiff's docklands. The retired officers all pleaded not guilty to the charge and were cleared after the Crown Prosecution Service (CPS) offered no evidence against the defendants, halting the five-month trial.