A woman who killed her father and torched his home in the deluded belief that he had caused her mother's death today failed in her Appeal Court bid to have her life sentence overturned.

Ann-Marie Pyle battered 77-year-old William Pyle with a poker and repeatedly stabbed him "in revenge" for her mother's death 16 years earlier.

Pyle - tormented by acute psychosis due to cannabis abuse - scrawled "Bin Laden did this" in pen above her father's fire place, before setting fire to his house in Stanley Street, Close House, near Bishop Auckland.

The 42-year-old then stripped off her clothes and ran naked from the smouldering house to where police and firefighters had gathered.

Pyle - of Brooke Street, Eldon Lane - received a life sentence after admitting manslaughter on the grounds of diminished responsibility at Teesside Crown Court in July last year.

A count of arson was left to rest on the file, while the sentencing judge also ordered that she serve a "tariff" of at least three years behind bars before being considered for parole.

Pyle appealed the life-term today - her lawyers claiming that she no longer presents a risk to the public - but her case was dismissed by top judge, Lord Justice Kay, sitting at London's Criminal Appeal Court.

The judge said the case had an "unusual and tragic history", originating in Pyle's childhood when she first showed signs of her unstable and erratic temperament.

Her family ran a prosperous Scarborough hotel for many years, but were struck by tragedy in 1984 when Pyle's mother committed suicide. In subsequent years the family encountered financial problems as the hotel business foundered.

After her mother's death Pyle went to live in America, but had a series of failed relationships, her behaviour becoming "increasingly unpredictable".

Lord Justice Kay said Pyle had formed the "deeply held perception" that her father was "responsible for the death of her mother".

In 1996 she even told one of her brothers' partners "that her father had murdered her mother and that she too would kill him".

There were also a number of occasions when she was seen to be "physically violent or verbally abusive" to Mr Pyle.

In the days before the killing she had travelled to her old home town of Scarborough, but was taken in and examined by a doctor at the police station after being seen wandering along a road on the outskirts of town.

Her father picked her up from Scarborough, driving her back to County Durham where the bloody events unfolded.

Mr Pyle - a well-respected member of the local community - received 86 wounds during his daughter's onslaught.

Pyle's counsel, Malcolm Swift QC, said she was no longer using cannabis and had come to terms with her earlier dependence on the drug.

Given that cannabis was the catalyst for her explosion of violence she could no longer be considered a risk, he argued.

Lord Justice Kay - sitting with Mr Justice Goldring and Mrs Justice Cox - said the sentencing judge had given the matter careful consideration, also taking account of the fact that she was no longer considered mentally ill.

He concluded: "It is manifest that he was making that decision not solely because the doctors said so, but because he was evaluating for himself the degree to which she would remain a danger in the future.

"His main concern was that, although she may have stopped using cannabis for the time-being, if she started again there was every reason to think that her disturbed behaviour might repeat itself.

"Having regard to the dreadful consequences of that disturbed behaviour, he concluded that that was a risk from which the public were entitled to be protected.

"We find it quite impossible to fault his approach to this difficult case."

The life sentence means that, after she is released, Pyle can be recalled to prison at any time if she puts a foot wrong.