A “troubled” young man” fatally stabbed his grandfather in the neck after finding out about sex abuse allegations, a court has heard.

Ben Oliver, himself a convicted paedophile, is accused of murdering 74-year-old David Oliver in his home in Mottingham on January 19 last year.

The Old Bailey heard how the pensioner was bedbound and immobile after suffering a stroke years before.

Prosecutor Louis Mably QC told jurors: “He was attacked and killed as he lay helpless in bed, in his bedroom on the first floor of the house.

“He had been repeatedly stabbed and slashed with a knife in the face, and in particular in the neck, which had effectively been cut open.

“It was a brutal attack, plainly carried out with the intention of killing him.”

The prosecutor said the 25-year-old defendant had become “very angry” after learning of allegations against his grandfather of historic sexual abuse of girls.

On the morning of January 19 last year, without warning, he took a kitchen knife, went into the bedroom, and killed David Oliver, the jury was told.

Mr Mably said the identity of the killer was not disputed and Ben Oliver had told his grandmother what he had done immediately afterwards.

He said the issue for the jury was the defendant’s mental state at the time and whether his responsibility was diminished, meaning he was guilty of manslaughter and not murder.

Mr Mably told jurors that the defendant grew up in “troubled and difficult times”.

In 2016, Ben Oliver was convicted of sexual offences against a young girl when he was aged 15, the court was told.

He was released from youth detention in September 2019.

In the months before the killing, he became aware of allegations of sexual abuse against his grandfather, who was also said to have treated his wife badly and had affairs, the court heard.

The defendant was also depressed and had suicidal thoughts, jurors were told.

Mr Mably said: “He was a troubled and angry young man.”

Ben Oliver, of Bexleyheath, south London, denies murder and the trial continues.

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