M’Naghten: The Man Behind the Insanity Defence

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The M’Naghten case is well-known within criminal law and probably one of the most influential judgments when it comes to criminal insanity. Although originating in England, the case has been discussed and applied in courts all over the world; from some US states to Tanzania, Norway, India and, of course, here in Australia.

But while the ‘M’Naghten defence’ continues to be an important principle within Australia’s criminal justice system, not many people are familiar with the story of the man at the centre of the case: Daniel M’Naghten.

The Story of Mr M’Naghten:

In 1843, Daniel M’Naghten was a 30-year-old Scottish lathe operator living in London. While living in Glasgow, France and then London, M’Naghten continuously complained that the Tories (an English conservative political party) were out to get him.

If he had been alive today, M’Naghten would likely have been diagnosed with paranoid schizophrenia – but no one took him seriously at the time.

M’Naghten often complained to police of persecution at the hands of the Tories and Catholics, claiming that they followed him everywhere. One day, M’Naghten was seen lingering suspiciously around the residence of Sir Robert Peel, a prominent Tory politician, who had served both as Prime Minister and Secretary of State.

M’Naghten had hatched a plan to shoot Peel, but the plan failed, when he mistakenly shot Edward Drummond, Peel’s secretary, who later died from the bullet wound. It wasn’t long before M’Naghten was facing murder charges – which carried the death penalty.

At trial, M’Naghten’s defence was that he was in an unfit state of mind at the time he killed Mr Drummond. He pleaded ‘not guilty’ on that basis, submitting that he was “driven to desperation by persecution.”

The impending trial garnered huge publicity; and final judgment would become the leading authority on the legal relationship between crime and mental illness.

What Did the Court Say?

The trial was held at one of England’s oldest and most famous courts, London Central Court, also known as the Old Bailey.

Police officers, doctors, M’Naghten’s father, landlady and a whole host of others testified in court.

The evidence of three defence doctors was that M’Naghten was insane and did not have control of his actions. One of these, Dr Edward Monroe, testified:

“I believe I am able to discriminate between a case where a man is labouring under delusion, and where a man feigns delusion. I am quite satisfied that the prisoner entertained the delusions he was giving utterance to. I have not the slightest shadow of a doubt on the subject.”

The prosecution agreed that M’Naghten was insane – but submitted that this was not enough to absolve him of guilt. The prosecution argued that M’Naghten was guilty because he knew that he was committing a crime, despite his deluded reasoning behind its commission.

The jury returned a verdict of ‘not guilty’ on the grounds of insanity without even retiring to the jury room.

But not everyone was pleased with the result – and no less than Queen Victoria wrote a letter to Sir Robert Peel complaining about the verdict. The Queen had also been the victim of unsuccessful assassination attempts, and was not too happy about the precedent that the case set.

The Privy Council Decision

The Parliament was likewise disappointed with the result, so they revived an ancient and obsolete right: to put questions to the House of Lords (a superior UK court) in order to clarify “the law respecting persons afflicted with insane delusions.”

Although the questions were framed in the hypothetical, it was obvious that they related to the infamous M’Naghten case.

The Privy Council noted with concern that too many people who were “unquestionab[ly] guilt[y]” were using the defence as a last resort to avoid execution. But on the other hand, they affirmed that genuine insanity was a complete defence, finding that:

“If the accused was conscious that the act was one which he ought not to do; and if the act was at the same time contrary to law, he is punishable… Every man is presumed to be sane and to possess a sufficient degree of reason to be responsible for his crimes, until the contrary be proved… A man cannot commit murder if he is labouring under disease of his mental faculties to such an extent that he does not know what he is doing, or does not know that it is wrong. But the defence of insanity has been so abused as to be brought into great discredit. It has been the last resort in cases of unquestionable guilty… [but] a man does not become irresponsible by the mere fact of being partially insane. Such a man may control over his passions as he had when in mental health.”

This meant that when a defendant claims to be insane, a medical person who has been present in court and heard the evidence can be asked whether, on the facts established by witnesses, the defendant was capable of distinguishing between right and wrong.

What Happened to M’Naghten?

After his acquittal, M’Naghten was sent to the State Criminal Lunatic Asylum. He died there from diabetes and heart problems in 1865, aged 52. Apart from one hunger strike, the rest of his life was relatively uneventful.

150 years later, M’Naghten’s case is still relevant when it comes to using mental illness as a complete defence to criminal charges.

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