Julie Kenyon, who was jailed for life in 2003 at the age of 46, was present in the dock at the Court of Appeal in London for the proceedings before three senior judges.

Her QC Paul Dunkels told them her appeal was founded on fresh expert psychological and psychiatric evidence relating to three confessions she made over the death of 89-year-old widow Irene Waters at the home they shared in Halifax, West Yorkshire, in 1996.

Mr Dunkels submitted that the evidence established that at the time she made those confessions she was suffering from a "personality disorder" and that the confessions should now be regarded as "unreliable".

That disorder, he argued, was "relevant and significant to any question about the reliability of any of those confessions".

Kenyon, of Dodge Holme Court, Mixenden, Halifax, was convicted by a majority verdict at Newcastle Crown Court of murder.

In a tape recording made by her sister Carol in a pub, Kenyon confessed to smothering her grandmother with a pillow because her grandmother had asked her to help her die.

Today's hearing follows a referral of Kenyon's case to the Court of Appeal by the Criminal Cases Review Commission, an independent body which investigates possible miscarriages of justice.

Kenyon's defence at trial was that she had made false confessions because she had felt under pressure from family members to confess and told them what they wanted hear.

Mr Dunkels told Lord Justice Hughes, Mr Justice MacKay and Mr Justice Lloyd Jones that her murder conviction was based solely on three confessions - one to her mother, another to family friend Kevin Donegan in 2001 and then to her sister.

An inquest held soon after the death of Mrs Waters concluded that she had died of natural causes.

The QC said: "Without those confessions there would have been no evidence of an unlawful killing at all."

Kenyon's appeal is being contested by the Crown. The hearing will last all of today and is then expected to be adjourned until February 19 for the legal submissions to be completed.