Britain's top prosecutor expressed extreme concern today after the collapse of a police corruption trial over the wrongful conviction of three men for the murder of prostitute Lynette White
Trial judge Justice Sweeney discharged the jury at Swansea Crown Court after ruling that the eight accused former police officers could not get a fair trial.
The eight were jointly charged along with two civilians in the biggest trial of its kind involving former police officers in UK criminal history.
But Simon Clements, the Crown Prosecution Service's reviewing lawyer, said the case collapsed after a review discovered that files had been destroyed.
Director of Public Prosecutions Keir Starmer QC has been notified and is "extremely concerned" about the outcome, the CPS said.
The officers were alleged to have colluded to pervert the course of justice, leading to the jailing of three innocent men.
Prostitute Miss White, 20, was stabbed more than 50 times at her flat in the docks area of Cardiff in 1988.
Mr Clements said prosecutors were satisfied before the trial that "this was a case which should go before a jury".
"However, at the request of the judge on 28 November, a review by the prosecution of a certain section of the unused material has uncovered that some copies of files, originally reviewed but not considered discloseable at that time, were missing," Mr Clements said.
"This information related to complaints made by one of the original defendants to the IPCC and another complaint relating to the investigation.
"On inquiry, it was found that these copies had been destroyed and no record of the reason for their destruction had been made by the police officers concerned. This was the first time that prosecution counsel or the CPS had been made aware of this destruction
"Although this relates to copies and not original files, it is now impossible to say for certain whether the copy was in fact exactly the same material that had been provided by the IPCC, reviewed and then destroyed.
"The destruction of those copies, along with the non-recording of the destruction, meant that it would be impossible to give meaningful re-assurances that no other material had been treated similarly, thus undermining the defence's confidence in the disclosure process.
"Given the stage reached in the proceedings, the correct course of action is to offer no evidence, thus inviting verdicts of not guilty and ending the trial."
South Wales Police Chief Constable Peter Vaughan backed prosecutors' calls for a "full and detailed review of the circumstances in which this decision has had to be made".
Stephen Miller, Yusef Abdullahi and Tony Paris were convicted of her murder in 1990 in what became known as a notorious miscarriage of justice.
Cousins Ronnie and John Actie, who stood trial with those who became known as the Cardiff Three, were acquitted at the time.
The three convictions and two acquittals came at the end of what was the second murder trial involving all five men.
But in 1992 the convictions of Mr Miller, Mr Abdullahi and Mr Paris were quashed by the Court of Appeal and they were released.
In 2003, Jeffrey Gafoor, a client of Miss White, pleaded guilty to her murder and is now serving a life sentence.
Mr Abdullahi, 49, died earlier this year.
The defendants were alleged to have forced innocent witnesses to agree to fictional events over 20 days of intensive questioning.
Most senior among them was ex-superintendent Richard Powell and ex-chief inspectors Thomas Page and Graham Mouncher.
They were accused of conspiring with Michael Daniels, Paul Jennings, Paul Stephen, Peter Greenwood and John Seaford to pervert the course of justice.
Civilians Violet Perriam and Ian Massey, together with Mouncher, were each accused of two counts of perjury.
All 10 defendants denied all the charges.
But the trial, which began in July and is likely to have cost millions of pounds, became "irredeemably unfair", the judge said.
The judge said "there had been a number of problems in relation to the conduct of the prosecution" and its "duty of disclosure".
More such problems had "emerged" during lengthy legal argument over the last four weeks, he said.
Outside court, Mr Page called for an inquiry.
He said: "I'm just relieved that it's all over now after six and a half years.
"This would have been my seventh Christmas on bail and we've just had stalling tactics from the prosecution.
"And, in fact, we proved, or my team proved, that any 'evidence' against me was completely dismantled and taken apart and there was no evidence at all against me."
He added: "I would like an investigation into the way this investigation was conducted because there were dawn arrests, we've had our phones tapped, we've been followed, we've had surveillance on us, for nothing at all.
"The investigation should be re-investigated by a team from outside South Wales."
Mr Page said he thought there had been a vendetta against him and other officers, adding: "We were treated completely different to every other witness, but that's for someone else to decide."
Anthony Barnfather, of law firm Pannone, which represented Mr Mouncher, 59, added: "It is particularly worrying that this is yet another large and expensive trial where the prosecution failed in its duty to disclose relevant material to the defence."