An aspiring writer who harboured delusions that his estranged wife was trying to poison him with organophosphates and set fire to him, bludgeoned her to death with a hammer.

George Storrier also believed that a powerful group of individuals was sending him coded messages warning him against his wife and tipping him off about her intentions.

Storrier was originally charged with murder but at the High Court in Edinburgh admitted the reduced charge of the culpable homicide of his wife Frances at her home in Dobson's Place, Haddington, East Lothian on April 13 last year by striking her repeatedly on the head with a hammer.

Storrier, 47, will now be detained in the State Hospital, Carstairs.

Mr Norman Ritchie, advocate-depute, told the court that the Storriers had married in 1977. At the time of her death Mrs Storrier, 45, worked as a systems information officer with the local authority.

From 1982 the couple lived in a flat at Winton House, Pencaitland, East Lothian. At first the marriage was happy, but problems developed because of Storrier's personality.

Latterly, Storrier did not work but his wife, having a responsible job, was able to provide him with a car.

When the couple separated in July 1998, Mrs Storrier got a tenancy in her own name in Haddington and appeared to have gained some independence from her husband.

Storrier had financial problems, and without his wife's full support couldn't maintain his flat. He was asked to quit.

He had started divorce proceedings and it appeared to have been accepted that the marriage was over, with divorce the best course of action. However, Mrs Storrier was worried about her husband's state of mind, particularly about his concern that he was having to leave the home he had lived in for some 17 years.

On Wednesday, April 14 last year she didn't turn up for work and a friend went round to her house to see what was wrong. Storrier was at the house and explained that his wife wasn't in.

Police were contacted because of concern at Storrier's presence and when officers forced entry through the rear patio doors that afternoon they found Mrs Storrier lying on the kitchen floor with her head in a pool of blood.

She had suffered nine major wounds to the head, one of which had caused a depressed fracture.

When Storrier was detained he admitted he had killed his wife. He made reference to his concern about being virtually homeless and being reliant on his wife to subsidise his car.

Storrier went on: ''I'm afraid I simply saw nothing in front of me except anger and just pure anger. That's what I saw, her taking advantage of the situation.

''To make sense of humiliation at that point, I killed her. I hit her with a hammer in the back of the head. I hit her in extreme anger and she did not fall. She cried out and I hit her as much as was necessary after that.''

Mr Derek Ogg QC, defence counsel, said it was clear from psychiatric reports that his client had been suffering from a mental disorder for some time before he committed the offence.

He had approached his GP over his concerns about delusions that his wife was poisoning him with organophosphates, a delusion that seemed to have arisen from a public debate on the subject at the time of the Gulf War.

Storrier also described friends as part of a group that were guiding him and sending him secret messages to protect him. He also believed, entirely without foundation, that his wife had been responsible for setting fire to a home where an elderly person had died.

Mr Ogg said that Storrier now understood he was suffering from a mental disorder and felt remorse for the death of his wife.

Lord Cameron heard psychiatric evidence that Storrier was suffering either from schizophrenia or a delusional disorder, with schizophrenia the more likely diagnosis.

In light of the seriousness of the offence psychiatrists felt it was important for the protection of the public that Storrier was kept in conditions of special security where he would require long-term psychiatric treatment.