Michael O'Brien had always protested his innocence

Dubbed the Cardiff Newsagent Three - Darren Hall, Michael O'Brien and Ellis Sherwood's convictions for the murder of newsagent Philip Saunders were quashed in 1999.

During their appeal, questions were raised during the about the conduct of investigating officers who were alleged to have shown a "systematic disregard" of the rules governing interrogation of suspects.

In February this year, the Crown Prosecution Service announced it would not bring charges against any officers.

And a statement from South Wales Police on Tuesday said it accepted that mistakes were made in "coming to terms with the Police and Criminal Evidence Act" which was introduced in January 1986.

"In line with other users of the criminal justice system," the statement read, "we experienced difficulties in interpreting various elements of the new legislation."

Investigating officer Stuart Lewis

Mr Saunders was attacked and by robbers outside his home in the Canton area of Cardiff in October 1987.

He died five days later in hospital.

All three men had served 11 years of a life term. They were convicted after Mr Hall 'confessed' to detectives.

During the hearing in December 1999, the Appeal Court heard that incriminating written evidence written by a senior detective, had been lost.

Prosecution witnesses Christopher Chick and Helen Morris - who later retracted their evidence claiming the police had put pressure on them - said they had been subject of intimidated and threats which involved former detective Stuart Lewis.

'Hadn't played ball'

Mr Chick also claimed that the police had offered him �5,000 for giving evidence against the men but was then refused it as he "hadn't played ball".

Mr Lewis, the appeal court also heard, was present when one of the three, Darren Hall, admitted being a look-out for the other two who, he was reported to have told detectives, attacked Mr Saunders.

But lawyers claimed their convictions were "unsafe and unsatisfactory" in the light of psychiatric evidence that Hall was unusually vulnerable and suggestible at the time.

Ellis Sherwood: Freed on appeal

The judges subsequently said the jury would probably have taken a different view of his evidence if it had known of Mr Hall's past history of telling lies.

But while criticising their detention at Canton police station, where Mr Hall and Mr O'Brien were handcuffed to a radiator, the judges said they could not make any findings of deliberate misconduct against any police officer. Convictions against all three were subsequently quashed.

Michael O'Brien - the most vociferous of the three - went on to become a director of the Miscarriages of Justice Organisation (Mojo) which campaigns for victims of miscarriages of justice.

The 32-year-old welcomed the news earlier this month that South Wales Police were planning to review the murder case.