LAWYERS for a convicted murderer claim advances in scientific techniques could prove he is the victim of a miscarriage of justice.

Kevin Nunn, a 51-year-old former salesman, is currently serving 22 years in prison for the murder of 37-year-old Dawn Walker.

Miss Walker’s body was found near the River Lark, close to her home in Fornham St Genevieve, Bury St Edmunds, in 2005. At the original trial in 2006, the prosecution said Nunn, who was Miss Walker’s former boyfriend, killed her out of jealousy.

But Nunn, formerly of Woolpit, has maintained his innocence throughout and yesterday, at the High Court in London, his legal team began their bid to force police to grant access to forensic evidence in the case.

During the hearing, Mr Justice Haddon-Cave and Sir John Thomas, President of the Queen’s Bench Division, heard from counsel acting for Nunn, Suffolk police and the Crown Prosecution Service (CPS).

Nunn’s team says some of the forensic evidence might shed new light on the case. But the police and the CPS say the evidence requested had little bearing on his conviction and warn granting access could open the ‘floodgates’ for similar applications, which are currently determined at the discretion of Chief Constables.

Hugh Southey QC, for Nunn, said three items found at the crime scene a fleece placed on Miss Walker’s body, tape used to tie her to railings and sperm found on her thigh could, if the same DNA was found on all three, prove a pattern which could point to the killer’s identity. He said the three items together might have a cumulative importance to the case which the material might not have in isolation.

“The ultimate issue is whether there is material which on testing might cast doubt on the conviction,” said Mr Southey.

“There is a clear public interest in preventing a miscarriage of justice. This is a case where evidence was circumstantial.”

He said Nunn was in a ‘Catch 22’ situation because in order to get a review of his case he needed to provide new evidence. But, said Mr Southey, he couldn’t get that new evidence unless the latest scientific testing techniques were brought to be bare on the forensic materials currently held by the police.

Fiona Barton QC, for Suffolk police, said the current guidelines for the disclosure of evidence “strikes the right balance” between preventing miscarriages of justice and ensuring a workable justice system. She said the Criminal Cases Review Commission, if it was to review the case, was looking for “evidence or material that is now available which might undermine a conviction”.

She added: “This is not an absolute right to go on a fishing expedition.”

Speaking about the sperm sample found on Miss Walker’s legs at the murder scene, Miss Barton said its origin was inconsequential because at no stage had the prosecution claimed it was from the killer. In fact, she said, the ‘very small’ sample - understood to be just five spermatozoa - might have got on Miss Walker’s legs from ‘secondary transfer’ such as her use of the men’s changing rooms at her gym in Fornham earlier in the day (the ladies’ was closed that day for refurbishment) or from her underwear.

“If it was Mr Nunn, then what does that show?” Miss Barton asked. “Nobody was saying the sperm was Mr Nunn’s.

“Even if one was to assume it (the testing of undisclosed evidence) comes out in Mr Nunn’s favour, it is impossible to see how that could undermine the conviction in this case.”

Julian Knowles QC, for the CPS, said: “Scientific issues were largely irrelevant in this case. The presence of other people’s DNA in this case could be wholly innocent.”

He said what Nunn’s legal team was seeking amounted to “a complete reinvestigation of the case” adding: “It is not the case that some new material has come to light. It is not a focused request for disclosure.”

All three parties in the case have a further seven days to make any submissions to the judges, who will return to the High Court at a later date to deliver their verdict.