Richard Thorpe, 26, struck father William Thorpe, 58, on the head with a plumber's wrench and repeatedly stamped on his head as he screamed for an ambulance to be called, Leeds Crown Court heard.

Thorpe had a history of mental illness starting in 2004 and had been treated in hospital.

But at the time of the killing on February 21 he was receiving treatment in the community and living at an address on Bradford Road, Batley.

His condition had deteriorated but Thorpe had tried to carry on as normal.

The killing outside victim Mr Thorpe's home in Howard Street, Batley, was heard by his daughter Melissa and witnessed by son Robert and neighbours.

Richard Thorpe denied murder but admitted manslaughter on the grounds of diminished responsibility.

The Recorder of Leeds, Judge Peter Collier QC ordered that Richard Thorpe be detained indefinitely under the Mental Health Act. Thorpe set off for his father's home just after 6am on February 21 to catch the road sweeper leaving for work after having delusions Mr Thorpe had sexually abused him as a child.

Prosecutor Neil Clark said: "He confronted his father saying something like: 'Who's the paedophile now?"And asked his father for one good reason why he should not hit him with the tool."

Mr Thorpe, a grandfather, denied the accusations but was struck on the head and fell down some steps screaming out that his arm was broken.

Daughter Melissa saw her injured father and screamed for Thorpe to stop but he stamped on his head ten times leaving him fatally injured with a skull fracture and brain haemorrhages.

Mr Clark said: "He (Thorpe) accepted he had lost it when he struck his father."

Psychiatrist Dr John Kent told the court at the time of the killing Thorpe was paranoid, deluded and suffering hallucinations.

Dr Kent said Thorpe's view that his father was a paedophile was "entirely a figment of his imagination."

Ordering that Thorpe be detained indefinitely, Judge Collier said: "I'm satisfied you are suffering from schizophrenia."