A woman who conspired with her nephew to murder her husband for a £450,000 insurance pay-out was jailed for life today.

Christina Button, 32, looked stunned as the judge at Newcastle Crown Court sentenced her for the ''calculated'' killing.

Her accomplice, Simon Tannahill, 20, was handed a life sentence yesterday after the pair were both found guilty by a jury.

Button's sentence had been postponed after she collapsed sobbing in the dock when the verdicts were read out. She had persuaded Tannahill to murder 53-year-old George Button as he walked his border collie near their home in West Rayton, County Durham.

Sentencing her today, the judge, Mr Justice Royce, said: ''George Button was a kind and gentle man. It is difficult to conceive of a more cold and calculating killing.

''There is only one sentence that I can pass and that is one of life imprisonment.''

The victim had been battered about the head at least six times when his body was discovered by a passer-by in March this year.

He died in hospital two days later and police had initially thought the blows were caused by a passing vehicle.

His wife had run up debts of nearly £200,000 and the couple had remortgaged their home to pay off money they owed as a result of her ''profligacy'', the trial heard.

The victim and Mrs Button had a seven-year-old daughter, Laura, and also shared their home with Tannahill at the time of the murder.

During the three-and-a-half-week trial, the jury was told that Tannahill had an unusually close relationship with his aunt.

He was described by his defence team as a man of previous good character and a ''gentle, quiet, and non-aggressive man.''

But Toby Headworth QC, for the Crown, had argued that, by the time of the killing, he had become ''besotted'' by his aunt, adding it was ''a fact she both knew and was happy to take advantage of''.

He said she had a long history of getting into financial difficulties and a ''penchant for spending heavily''.

During the 12 months leading up to her husband's death she had been running 14 credit and store cards and the debts were rising.

With overall debts including the mortgage on their home in St Mary's Drive at £197,000, he argued that there was a clear motive for Mrs Button's involvement in the death.

Mr Headworth had told the court: ''The mathematics were, we submit, straightforward.

''Christina Button may not have known the exact figures but from being heavily in debt she could walk away with a detached house fully paid for and a profit of £250,000.

''Christina Button, we say, was acutely aware of the benefits to her of her husband's death.''

She had told neighbours that, thanks to insurance polices and her husband's age, she would one day become ''a very rich young widow''.

Mr Button had been described as a well-liked, hard working, quiet and unassuming man with no enemies.

He had worked as an electrician at a coal pit in Philadelphia and then for Sunderland City Council, remaining single and living with his parents at their terraced home in Shiney Row until their deaths.

He inherited the house and was living there when he met Christina.

The pair spent a lot of money redecorating before moving to the modern semi-detached home in West Rayton where they lived at the time Mr Button was killed.

Tannahill was also living with them at the time after staying with various other relatives following a row with his father which led to him leaving the parental home.

After the verdicts yesterday, George Button's brother Fred, 58, from East Rayton, said: ''I think George has received the justice he deserves. The people who were concerned in his murder got their just deserts.''