A WOMAN bludgeoned her elderly father to death after developing "acute paranoid psychosis" because she was addicted to cannabis, a court heard yesterday.

Bill Pyle, 77, suffered 85 wounds in the onslaught after his daughter flew into a violent rage attacking him with a poker, a walking stick and a knife.

Experts who examined 42-year-old Ann-Marie Pyle concluded the rage had been brought on by years of cannabis abuse.

The killing - which took place in Close House, near Bishop Auckland, County Durham, in November last year - has reignited the debate over Government plans for cannabis.

Only last week, Home Secretary David Blunkett confirmed that possessing the drug would no longer normally be an arrestable offence, although it will remain illegal.

Last night, anti-drug campaigners said the tragic case proved the Government was wrong to downgrade the drug.

Teesside Crown Court heard how heavy cannabis use fuelled paranoid delusions that Pyle had about her father.

And psychiatrist Professor Don Grubin, of St Nicholas's Hospital, in Gosforth, Newcastle, told the court that Pyle could be a future danger if she ever took the drug again.

Pyle, of Brook Street, Eldon Lane, Bishop Auckland, pleaded not guilty to murder. The Crown Prosecution Service accepted a plea of guilty to manslaughter by reason of diminished responsibility.

Judge Mr Justice Holland jailed her for life.

The court heard how Pyle attacked her elderly father - who lived in a home owned by Bradford City goalkeeper Aidan Davison - because she blamed Mr Pyle for her mother's suicide.

Pyle then wrote "Bin Laden did this" in felt tip pen on the living room wall above her father's battered body before setting fire to his house in Stanley Street, Close House.

Experts who assessed Pyle said that at the time of the tragedy she had been suffering a serious mental illness but had now recovered.

They said the only explanation for her recovery was the fact she was not using cannabis in jail.

The court heard how Pyle blamed her father for the death of her mother, Ellen, who had committed suicide after her extra marital affair had ended.

The family's previously successful hotel business in Scarborough had also folded and the two tragedies had led to her behaviour becoming increasingly erratic and volatile.

She had subjected her father to years of verbal and physical abuse, said Aidan Marron QC, prosecuting.

Malcolm Swift, defending, said she harboured a growing belief that her father had been responsible for her mother's suicide - a delusion fostered by cannabis misuse.

He added: "Two experts prepared reports, one that she was capable of extreme violence. He said that her use of cannabis caused an acute paranoid psychosis.

"Another said that the killing was the result of mental illness now resolved, but in the long term it was conceivable that if she returned to cannabis use the risk could increase."

Campaigners opposed to the Government's "softly, softly" approach to cannabis use called for a rethink last night.

David Hinds, of the North of England Victims' Association, said: "This tragic case clearly demonstrates the stupidity of downgrading cannabis.

"Clearly the assumption that cannabis causes no long term harm was very wrong in this instance.

"It's not too late for the Government to rethink the disastrous course of action it has embarked upon."