Vital evidence in the Nat Fraser murder case was not disclosed to his lawyers becuase of an "extraordinary degree of incompetence", a court heard today.

Nat Fraser, a convicted wife killer, appeared in court today to begin his appeal to clear his name.

He is trying to overturn his conviction for murdering his estranged wife Arlene nine years ago.

Fraser, 48, was jailed for life in January 2003 after a jury convicted him of the killing.

Fraser's trial heard that three of Mrs Fraser's rings went missing on the day she disappeared then mysteriously turned up in the bathroom of her home nine days later.

It was claimed her husband had placed them there, suggesting he had access to her body after she vanished.

However, two Grampian Police officers - Constables Neil Lynch and Julie Clark -whose testimony was not heard at the trial, have claimed they saw the rings in the bathroom just hours after the mother of two went missing.

Today, Fraser's lawyer, Peter Gray QC, blamed "an extraordinary degree of incompetence" for the failure to reveal information about Mrs Fraser's rings.

He said the evidence had the potential to "fundamentally undermine" the cornerstone of the case against Fraser.

The appeal is being heard by Lord Justice Clerk Lord Gill, Lord Osborne and Lord Johnston.