An Addiscombe woman has admitted killing her elderly mother by giving her insulin and smothering her with a pillow.

Shirley D'Silva, 55, was psychotic and hearing voices when she attacked 77-year-old Martha Pereira at the family home.

On the first day of her murder trial at the Old Bailey, she pleaded guilty to the lesser charge of manslaughter on the basis of diminished responsibility, which was accepted by the prosecution.

D’Silva dialled 999 on October 25 last year at about 4.10pm and told the operator she had just killed her mother.

When the operator asked what happened, she replied: "Erm, nothing happened. I just decided to take her life."

When the operator asked D’Silva "what made you do this today?" she replied: ''It's the world we live around.

"We've been suffering too long. Nobody's doing nothing about it. Somebody has to come forward and do something about it."

D’Silva told the operator her mother had been unwell for a long time.

Later on in the call when asked by the operator "did you do it because you don't think you were getting the help you needed?" she replied: "No, no. It's not, it's not that. It's about the world, the war around the world going on."

D’Silva remained on the phone until officers arrived at the scene.

She remained calm at first and when asked what happened, D’Silva told officers: "I have just killed my mother. I have given her an overdose of insulin and I have suffocated her with a pillow."

Officers and paramedics from the London Ambulance Service carried out CPR on Mrs Pereira but she was pronounced dead a short time later at a south London hospital.

A post-mortem examination showed the cause of death was consistent with an insulin overdose and smothering.

When she was later interviewed by police, D’Silva told them a man had told her to kill her mother, and he was now telling her to kill her husband and son.

D'Silva, of Morland Road, was remanded in custody to be sentenced by Judge Nicholas Hilliard QC on Tuesday.