A jilted lover murdered his ex's brother in an act of revenge before attempting to kill himself with a harpoon, a court has heard.

Young chef Henry Stangroom was found on his bed in a pool of blood with wounds to his chest and head at his flat on Lavender Sweep, Battersea, London on October 17 last year.

His flatmate Andrew Morris, dumped by the 21-year-old victim’s sister Michelle six weeks earlier, was found in the bathroom with slashed wrists and a harpoon spear stuck in his chin, the Old Bailey heard this morning.

Opening the trial Sarah Plaschkes, prosecutor, told the jury there was no dispute that the defendant had killed Mr Stangroom and that the defendant had cut his own wrists and fired the spear into himself.

She said: "The prosecution say this was a killing motivated by revenge.

"The relationship between the defendant and Michelle had ended.

"She had rejected him. Killing her brother was a way of taking revenge on her for the hurt and distress she had caused him."

The jury heard that Mr Stangroom had moved to London in January last year to live with his sister in Lavender Sweep, Battersea.

He had got a job as a chef at the Criterion Restaurant in Piccadilly Circus.

Miss Plaschkes said the relationship between Mr Stangroom’s sister and Morris ended six weeks before the alleged murder, after the two had an argument during which Morris became violent, throwing her onto a sofa and putting his hands over her mouth.

Miss Stangroom then left the house in Lavender Sweep to stay with friends and her brother was due to move out the weekend after he was murdered, the court heard.

The 21-year-old was last seen walking back home after having drinks with work colleagues on the evening of October 16.

The house in Lavender Sweep, Battersea

At 2.30am the following morning a neighbour, Madeline Irani, heard noises, Miss Plaschkes said.

She added: "She heard three or four thumps and then shouting like a woman’s voice crying out ‘ah, ah, ah’."

Concerned that she could not contact her brother that day, Miss Stangroom went to the house that evening just as police officers arrived having been called by her family, the court heard.

Morris was taken to hospital and was later charged with Mr Stangroom’s murder.

In interview he gave a statement to say he could not remember anything after he saw Miss Stangroom a few days before the alleged murder.

Miss Plaschkes said that among the items found in the house were a blood-stained kitchen knife, a bloodied hammer and several bloodied clothes.

A phone belonging to Morris was also examined, Miss Plaschkes said, which contained internet searches for ‘spear gun death accident’ and ‘murder by mental health illness’.

Miss Plaschkes told the jury the defendant now claims to remember some aspects of that night and will argue that the attack was self defence.

If that defence fails, she added, he is expected to argue the killing was manslaughter on the grounds of diminished responsibility.

Morris, 30, of Lavender Sweep, Battersea, denies one count of murder.

The trial is expected to last eight weeks.