A "compulsive spender" said to have plotted her husband's murder so as to clear her mounting debts today won the right to challenge the safety of her conviction in London's Appeal Court.

Christina Button, 33, was jailed for life in December last year alongside her nephew, Simon Tannahill, over the callous slaying of her "gentle giant" husband, George. The prosecution claimed Tannahill, then 21, ambushed Mr Button, 52, while walking his dog down a quiet lane near the couple's home in St Mary's Drive, West Rainton Co Durham in March 2003.

It was claimed that Button and her nephew plotted together to carry out the murder, while Button was allegedly motivated by pressure from mounting debts.

Giving Button permission to appeal her conviction Lord Justice Judge said the Crown claimed she was a "compulsive spender who arranged for Tannahill to attack and kill her husband because she was in considerable debt and stood to make a huge financial profit after his death".

Her QC, Alistair Webster, challenged the conviction on grounds that the trial judge should have excluded evidence of a video recording taken at the police station where Button was allegedly depicted telling Tannahill not to tell police anything.

Lord Justice Judge said it was argued that the admission of evidence breached Button's rights under Article Eight of the European Convention on Human Rights - the right to privacy.

The judge gave permission to appeal, ordering that the case be heard on February 28 - with a three-hour estimate. He also urged Button not to be over-optimistic about the outcome.

Mr Button died within days of the alleged attack, with his wife at his hospital bedside. In the months that followed she showed every sign of being a widow in mourning, sending flowers to the crime scene and placing memorial notices in the local declaring her undying love for George.

Button, who has steadfastly denied masterminding the murder, was said to have an "uncontrollable spending obsession", having allegedly clocked up £200,000 in debts.

Mr Webster took issue with the trial judge's admission of three pieces of evidence - the police station video footage, evidence about a past theft from employers, and testimony from neighbours about her lavish spending habits.

He said this last cluster of evidence had done nothing to strengthen the Crown's case on motive, but "created a very unpleasant picture of her which would have been very disadvantageous to her".

There was also "no lawful authorisation" for police shooting the video footage, since officers had only secured permission to use audio material, he told the court. In those circumstances the video evidence should also have been barred from trial.