Written evidence of an incriminating conversation between two men convicted of murdering a Cardiff newsagent has been lost, the court of appeal in London has been told.

It was written by a senior detective central to the police investigation into the death of Philip Saunders in 1987.

The note was jotted down onto the back of an expenses claim form by former detective Stuart Lewis.

The appeal court heard that he had gone to the cells in Canton Police Station in Cardiff, where Michael O'Brien and Ellis Sherwood were being held.

Mr Lewis had hoped the pair would discuss the murder of newsagent Mr Saunders who had been killed at his Cardiff home in October 1997.

The newsagent died in hospital five days after being robbed in a savage attack.

He had been struck over the head with a shovel and was never able to identify his attackers.

The appeal court was told that both O'Brien and Sherwood insisted the conversation noted down by Mr Lewis did not take place.

Bob Marshall Andrews, QC, Sherwood's barrister questioned Mr Lewis over why he had not recorded the conversation in his pocket book.

He described Mr Lewis as a central senior figure in the investigation.

Mr Andrews said two key prosecution witnesses said Mr Lewis was involved in threats and inducements made to them to get them to repeat their evidence in court.

Christopher Chick and his girlfriend Helen Morris later admitted lying during the trial.

They retracted their evidence saying police put pressure on them.

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

The court was also told that Mr Lewis had been present when a third man, Darren Hall, admitted being the look-out while Sherwood and Ellis attacked the newsagent.

Hall, 30, from Newport, Gwent, O'Brien, 31, and Sherwood, 30, both from Cardiff, were sentenced to life after being convicted of Mr Saunders' murder in July 1988.

Both Sherwood and O'Brien have always denied any part in the robbery or killing, also asserting Hall's innocence.

Lawyers for the three now claim their convictions were "unsafe and unsatisfactory" in the light of psychiatric evidence that Hall was unusually vulnerable and suggestible and that his confession could not be relied upon as true.

However, the Crown maintains there is still enough evidence to uphold the guilty verdicts.

The appeal hearing continues.