A devoted mother who feared her brain-damaged son would die in agony gave him a lethal heroin injection to end his life "peacefully and painlessly", a court heard today.
Frances Inglis, 58, of Dagenham, east London, who was jailed for life for murder, had believed 22-year-old Tom was in "constant pain", her barrister told three Court of Appeal judges in London.
Inglis, who is present in the dock of the court, is challenging her conviction.
She was ordered to serve a minimum term of nine years in January after being found guilty of murder and attempted murder by a jury at the Old Bailey.
Alan Newman QC, making submissions on her behalf today, said: "She was entirely taken up with the belief that Tom was suffering and that he was trapped in a sort of living hell and in pain.
"She was no longer the person her family, friends and colleagues had once known."
He told the Lord Chief Justice, Lord Judge, sitting with Mr Justice Irwin and Mr Justice Holroyde, that before the tragic events Inglis was "a devoted mother, a perfect lady, a person of impeccable character" who had worked for many years helping disabled people.
After the conviction, her family said they were standing by her over Tom's death.
Mr Inglis suffered severe head injuries when he fell out of a moving ambulance in July 2007.
His mother, who worked as a carer for disabled children, first tried to end his life two months after the accident when he was being treated at Queens Hospital in Romford, Essex.
His heart stopped for six minutes but he was revived.
The mother-of-three was charged with attempted murder before successfully trying again in November 2008, after barricading herself in her son's room at the Gardens nursing home in Sawbridgeworth, Hertfordshire, and supergluing the door.
Inglis gave an emotionally charged account to jurors of how she had "no choice" but to end his life and had done it "with love".
She said: "For Tom to live that living hell - I couldn't leave my child like that."
But Judge Brian Barker, the Common Serjeant of London, directed the jury that no-one had the "unfettered right" to take the law into their own hands.
Jurors returned majority verdicts of 10-2 and the judge told them: "You could not have had a more difficult case."