44-year-old Satpal Kaur Singh from Barking in east London killed her son Ajit by making him drink bleach because she feared social workers would take him away, the Old Bailey Court heard.
Earlier, Singh had refused to co-operate with council staff at a meeting over his care. She had appeared "calm" at the time and no one else who attended the meeting had "any concerns about her immediate behaviour", the court heard.
Hours later she rang police to say: "I've just killed my son and I've tried to kill myself." The court heard Singh had made her son drink a cup of bleach at around 8 pm on February 9 and then drank some herself an hour later.
Singh, who had earlier denied murder, pleaded guilty to manslaughter yesterday by reason of diminished responsibility. She was remanded in custody to be sentenced on December 13.
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