The appeal by Frances Inglis against her murder conviction for taking the life of her brain-damaged son to end his "living hell" threw the spotlight on the current state of the law relating to the "profoundly sensitive" issue of mercy killing.
As three top judges rejected her challenge, they said there was a wider public interest in the case "because the issues to which it gives rise are immensely sensitive and difficult, and they have attracted an increasing measure of public interest and concern".
Ruling in what is believed to be the first murder involving a "mercy killing" to reach the Court of Appeal, the Lord Chief Justice, Lord Judge, emphasised that "the law of murder does not distinguish between murder committed for malevolent reasons and murder motivated by familial love".
A mercy killing which is not committed in circumstances of provocation or diminished responsibility "is indeed murder".
Inglis, 58, of Dagenham, east London, who injected her 22-year-old son Tom with a lethal dose of heroin, believed that for an offence to be murder it had to be carried out with hatred.
At her trial, she told how she wanted her son to leave what was a living hell. She said she felt that he had already lost his life.
She said she did not see it as murder and there was no malice, only love in her heart.
Lord Judge said the appeal court, in deciding her appeal, was constrained "to apply the law as we find it to be".
He stated: "How the problems of mercy killing, euthanasia and assisting suicide should be addressed must be decided by Parliament, which, for this purpose at any rate, should be reflective of the conscience of the nation."
In a true case of mercy killing, he said, provocation "is unlikely to provide any defence".
The judge added: "The more likely defence would be diminished responsibility."
Either defence would reduce murder to manslaughter - but it "could not result in an acquittal".
Diminished responsibility was not advanced as a partial defence in Inglis's case.
Lord Judge said: "The latest statute to address the problem of mercy killing, currently in force, expressly includes as mitigation for the offence the offender's subjective belief that he or she was acting out of mercy, but that belief and motivation, however genuine, does not and cannot constitute any defence to the charge of murder."
The British Humanist Association (BHA) said the law needed to be reformed to distinguish between cases of "mercy killing" and murder.
Naomi Phillips, BHA head of public affairs, said: "Today's judgment demonstrates that the courts are bound by a restrictive law which fails to distinguish between where a person has compassionately assisted another to die, and where that was done with malicious intent or murder.
"However, it is for parliamentarians not judges to make the legal changes necessary in order to ensure that cases of 'mercy killing' and of murder are seen and treated differently under a reformed law.
"Ultimately, we want assisted dying to be legalised in the UK. Without those legal reforms, those who are vulnerable remain at risk because legal safeguards, which would accompany the legalisation of assisted dying, are not in place to protect them from coercion or other malice.
"We need a law on assisted dying that is sensible, ethical and forward-thinking, that both upholds people's fundamental human right to die with dignity, in a manner of their choosing, and which protects those who are motivated by compassion to assist another's death."Reuse content