A mother who made her 12-year-old autistic son drink a cup of bleach because she feared social services would take him away has pleaded guilty to his manslaughter.
Satpal Kaur Singh, 44, killed her son Ajit just hours after she refused to co-operate with council staff at a meeting over his care.
But she had appeared "calm" and no one else who attended the meeting was concerned about her immediate behaviour, the Old Bailey heard on Monday (local time).
Hours later she rang police to say: "I've just murdered my son and I've tried to kill myself."
The court heard that social workers at Barking and Dagenham Council had concerns about Singh in the months before she killed her son on February 9 this year, the Press Association reported.
Singh denied murder but pleaded guilty to manslaughter by reason of diminished responsibility.
Prosecutors accepted the plea after psychiatrists assessed that she was suffering a mental disorder.
"This is a case of great tragedy," said prosecutor Richard Whittam.
He said Singh feared social services were going to make an interim care order that would result in the boy being taken away.
Whittam said Ajit was dependant on his mother for all his needs, could not speak and had difficulty getting around outdoors.
"He could not tolerate crowded places or noisy environments. He would cover his ears and scream," he said.
The court heard that there had been many child protection conferences and Singh had attended some.
She had also made complaints against a number of people, including her husband, neighbours and members of social services.
"A neighbour who has known Satpal for over 10 years describes her as blowing everything out of proportion and not being capable of talking reasonably with anybody," Whittam said. "It was as if everyone was persecuting her."
Singh had previously spoken about killing herself by drinking bleach because of her problems with social services.
"Social services had concerns about a number of things, including Satpal's parenting skills and her lack of cooperation," the prosecutor said.
Singh was remanded in custody to be sentenced on December 13.