A man who killed his best friend on Christmas Eve showed “clear thinking” before the attack, a court has heard.

Dylan Thomas, 24, repeatedly stabbed William Bush, 23, on December 24 2023 at the home they shared in Llandaff, Cardiff.

Thomas, who was 23 at the time, has admitted manslaughter but denies murder.

The defence argued Thomas was mentally unwell at the time of the incident, insisting there was a “gamut” of signs of psychosis.

If he is suffering psychosis with the fear Mr Bush was going to kill him, why on earth was he going there?

However, the prosecution disagreed, insisting that Thomas showed “clear thinking” ahead of the attack.

Giving the prosecution’s closing speech on Wednesday, Greg Bull KC, said they accepted Thomas is schizophrenic, but argued the defendant intended to kill his friend.

Mr Bull said Thomas was not experiencing voices that told him to kill Mr Bush – as can happen in other cases of schizophrenia – and that searches for the veins and arteries of the neck suggested intent.

“This is not a case of the death being caused by voices – ‘I was told to do this by some voice, a spirit, by my dead ancestors’,” he said.

“There’s no previous illusion with Mr Bush appearing to be threatening.”

He told the jury that 16 of the 37 stab wounds to Mr Bush were to the front and back of the neck.

While Thomas had told his grandmother he wanted to go back to his house to walk the dog, Mr Bull argued Mr Bush was the object of the trip.

He said: “If he is suffering psychosis with the fear Mr Bush was going to kill him, why on earth was he going there?”

Orlando Pownall KC, speaking on behalf of the defence, argued the only explanation for Thomas’s actions was his mental state, insisting there was no “discernible motive” in this case.

Addressing the jury, he said: “You must acquit if you think there is a mental health explanation.”

He added: “There is a whole gamut of signs demonstrating psychosis.

“Why would a young, inoffensive man take his grandmother to his address intent on slaughtering his best friend?

“The prosecution says the fact that he was schizophrenic is irrelevant, we submit that it wasn’t.”

Mr Pownall said it was not in dispute that Thomas had initiated the attack and he had not acted in self-defence.

The trial continues.