Dylan Thomas, grandson of Sir Stanley Thomas, stabbed William Bush to death because he was moving out

The heir to a £230 million pie and property fortune stabbed his housemate to death in a frenzy after he decided to move out to live with his girlfriend, a court heard yesterday.

Dylan Thomas, the 24-year-old grandson of pie and property tycoon Sir Stanley Thomas, is accused of using a kitchen knife to kill William Bush, 23, with whom he had been best friends since they attended the same public school.

The two men had taken holidays and played golf together. But the ‘dynamics of their relationship’ changed after Mr Bush began making plans to move out of their shared house in Llandaff, Cardiff, and set up home with his girlfriend Ella Jeffries, a jury was told.

On Christmas Eve last year Thomas attacked him with two knives, severing the jugular vein, Cardiff Crown Court heard. A bloodied Mr Bush staggered outside saying: ‘Help me – I’ve been stabbed!’

But he collapsed on the patio in front of shocked Christmas shoppers in the well-off suburb, dying from 21 neck wounds. Thomas has admitted manslaughter but denies murder, claiming diminished responsibility.

However prosecutor Greg Bull KC told jurors it was ‘very significant’ that the night before the killing, Thomas had carried out an internet search on the anatomy of the neck.

Two months earlier, a ‘frightened’ Mr Bush had barricaded himself into his bedroom after his friend allegedly talked of killing him, Mr Bull said.

The pair met when they were pupils at £39,000-a-year or more Christ College in Brecon, moving into the property, part of Thomas’s grandfather’s property portfolio, with Mr Bush initially working as a surveyor.

But last year, ‘athletic’ Mr Bush, a keen golfer who ‘shied away from confrontation’, began ‘looking forward to starting a new job and setting up home with his partner’, Mr Bull said.

‘Dylan Thomas was a loner, and his only real friend was Will,’ he added, saying he ‘relied heavily’ on Mr Bush.

‘He was of slight build, Mr Bush was by far the stronger of the two men.’ The prosecutor said the ‘dynamics of their relationship was changing’, and Mr Bush had told Ms Jeffries that Thomas had said: ‘I thought or wondered about killing you.’ As a result he had ‘barricaded his bedroom door’ to prevent Thomas entering while he slept.

Thomas spent the night before Christmas Eve with his grandmother, but had been ‘unable to settle’, the trial heard. The following day, she gave him a lift home after he said he wanted to walk his dog, which was being looked after by Mr Bush.

Leaving his grandmother outside in the car, jurors were told Thomas went inside, armed himself with a kitchen knife and a flick knife, and went to Mr Bush’s bedroom where he attacked him from behind.

As Mr Bush fled, his friend pursued him and stabbed him repeatedly, severing the major blood vessel in his neck, the court heard.

Mr Bull said it was ‘significant’ that the night before, Thomas accessed a chart showing the location of the jugular vein. ‘It indicated that Mr Thomas was formulating an intention to attack and kill Mr Bush,’ he told jurors.

When police arrived, Thomas said he had acted in self-defence, saying Mr Bush had ‘gone mental’ and stabbed him with the knife after smoking cannabis.

Jurors were told there was ‘no doubt’ Thomas was ‘beginning to suffer from psychosis’ in the run-up to the killing. A month earlier he had been arrested ‘for trying to climb into Buckingham Palace’, jurors heard.

But Mr Bull said: ‘It is the prosecution case that Mr Thomas knew full well what he was doing.’

Thomas appeared via video link from Ashworth High Secure Hospital near Liverpool, where he has been held since his arrest.

The trial continues.