Pat Regan doted on her 21-year-old grandson Rakeim Regan, but he developed severe paranoid schizophrenia which made him delusional, Leeds Crown Court heard.

Hours after he left hospital with the support of his doting 53-year-old grandmother, Regan turned on her, stabbing her to death in a frenzied attack.

Rakeim's counsel Graham Hyland QC told the court yesterday that Mrs Regan wanted him home on medication instead of in hospital "and tragically that wish born out of love and concern for the welfare of her grandson cost Pat Regan her life the following morning".

Rakeim then went to Leeds City Station and stabbed a duty station manager who tried to stop him going on to the railway lines before he was arrested.

The tragedy was outlined yesterday when the 21-year-old denied the murder of Mrs Regan at her flat in Marlborough Grange, Leeds, but admitted her manslaughter on the grounds of diminished responsibility.

He also pleaded guilty to wounding David Clarke with intent on June 1 last year.

Ordering Rakeim to be detained indefinitely in high security Rampton Hospital under the Mental Health Act, the Recorder of Leeds, Judge Peter Collier QC said the circumstances were tragic on any view.

Regan's family had become increasingly concerned about his deteriorating mental condition and sought help from a GP and mental health staff at St James's Hospital.

The judge told Rakeim: "However your family wanted, and particularly your grandmother, to have you looked after at home. She didn't believe she was at risk from you."

Witnesses spoke of the love between grandmother and grandson. "At that time your paranoia focused elsewhere and her determination to care for you is typical from what I have heard of her indomitable character."

He said sadly in his deluded state the defendant went on to kill his grandmother and stab Mr Clarke at the station.

Expressing his sympathy to the Regan family the judge said their loss was felt not only in Leeds but the wider community.

He said no criticism was made of the mental health professionals in the case who had to make difficult decisions, but it was possible some lessons might still be learned such as the weight to be given to the relatives' wishes.

Jeremy Richardson QC, prosecuting, said Mrs Regan was a well known anti-gun and knife campaigner who had previously worked with Leeds Women's Aid and an organisation caring for prostitutes.

She had become a vocal campaigner with Mothers Against Violence after her own son Danny was shot dead in 2002.

Rakeim was her first grandchild. His parents had separated but he still remained in regular contact with his father, who lived in London, while his grandmother helped his mother with his upbringing.

Last February he was the victim of a stabbing and after that his family noted a change in him. He stopped looking after himself.

On May 29 he was arrested on suspicion of a burglary and although released without charge the next day was upset about his treatment and began behaving increasingly bizarrely talking about spiders crawling over him in the police station.

Mrs Regan had already involved the family GP, Dr David Watson, earlier in the month because she believed her grandson was depressed. The doctor saw him on May 19 but Rakeim declined help.

The doctor believed he was suffering a psychotic illness and decided to call in the Crisis Resolution Team. Rakeim agreed to see someone, but before he was seen his condition got worse.

On May 31 he was ranting and incoherent to his father on the phone and spoke of aliens being after him. Mrs Regan agreed Rakeim should visit his father, telling him he had never shown any violence and telling him she still felt safe with her grandson although "he isn't right in the head".

But when his behaviour became more bizarre, speaking of reptiles being all over the place, family members took him to St James's Hospital that evening.

He was assessed by a mental health nurse and it was decided he could be treated in hospital or allowed home with medication.

Mr Richardson said Mrs Regan requested her grandson be allowed home. She was given a sleeping tablet for him and arrangements were made for the crisis team to be in contact the next day.

Later that morning of June 1 she told a friend she had watched Rakeim during the night, at first he had been hyper-elated but eventually had slept.

Neighbours subsequently heard the sounds of shouting from her flat and it was then he stabbed her in the head and neck as she tried to fight him off. He told a friend later he thought she was a paedophile going to sexually assault him.

Her body had not been found when he went to Leeds City Station and briefly jumped on to the track.

Mr Clarke and other staff tried to prevent him going to another platform where they feared he was going to jump in front of a train.

It was then Rakeim produced the knife and stabbed Mr Clarke twice in the shoulder. He was commended for his bravery by the judge.