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General defences - insanity

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In 1800 James Hadfield was found to be insane on a charge of the attempted murder of George III, he received an outright acquittal.


Public and political reaction to this case led in turn to the enactment of the Criminal Lunatics Act 1800 which required the courts to order anyone who had been acquitted by reason of insanity of various serious offences to be detained until His Majesty's pleasure be known.


The law on insanity has developed both in Common Law (rulings by the judges) and through Acts of Parliament.


Sometimes referred to as "insane-automatism"

The defendant can raise insanity as a defence when he was suffering from mental disturbance or impairment, caused by an internal factor at the time of the act.

Automatism, sometimes referred to as "non-insane-automatism"

If the impairment is caused by an external factor the defence can raise automatism.

Before trial starts

Insanity may also be an issue at the beginning of the trial itself. As to fitness to stand trial Pinochet (1999).


Whether D is fit to plead is decided by the judge not the jury.  Before 2005 it was decided by the jury.



When the judge finds that the defendant is unfit to plead, the jury will decide whether the defendant did the act or made the omission, sec 22 Criminal Procedure (Insanity and Unfitness to Plead) Act 1991.


Murder / assaults / magistrates

Insanity is most often thought to be pleaded in murder cases, but the statistics show that it is more frequently used in assault cases.  It is not confined to major trials, but can be accepted in magistrates' courts (R (on the application of Singh) v Stratford Magistrates Court [2007] QBD, D assaulted a police officer).


Burden of Proof

The prosecution, defence or the judge can raise the issue of insanity.

The defence have the reverse burden of proof it they raise the issue.


This onus does not contravene the HRA or the ECHR, it is to the benefit of the accused, R v H [2003] HL.



In 1843, Daniel M'Naghten, intending to murder Sir Robert Peel (the Prime Minister), killed his secretary by mistake.


The court acquitted him on grounds of insanity. 

The court formulated the so-called M'Naghten rules that have "‘become the comprehensive definition of insanity" Sullivan (1984).

Whole case here


M'Naghten rules

Firstly, all defendants are presumed sane.

  1. On a balance of probabilities, the defendant must prove that at the time the offence

  2. He was labouring under such a defect of reason, arising from a disease of the mind,

  3. That he did not to know the nature and quality of the act he was doing, or,

  4. If he did know it that he did not know that what he was doing was wrong.

Effects of the Criminal Procedure (Insanity) Act 1964 and the Trial of Lunatics Act 1883

Special Verdict

The jury can return a special verdict of "not guilty by reason of insanity”. 


As it amounts to an acquittal, there is no right of appeal, (R v Felstead [1914]).  There is an appeal against the Hospital Order which often follows.


Sentencing since 31 March 2005:


D unfit to plead or not guilty by reason of insanity


For murder indefinite hospitalisation Sec 24(1)(3) Domestic Violence, Crime and Victims Act 2004.


For all other offences sentencing is prescribed by Section 5 Criminal Procedure (Insanity) Act 1964 as amended by Sec 24 Domestic Violence, Crime and Victims Act 2004 which sets out the powers to deal with persons not guilty by reason of insanity or unfit to plead.


The new sec 5 and 5A Criminal Procedure (Insanity) Act 1964 sets out the three disposal options where a defendant is found unfit to plead or not guilty by reason of insanity:

  1. Hospital Order under sec 37 Mental Health Act 1983.

  2. Supervision Order. This is described in detail in Schedule 2 to the 2004 Act, which introduces a new section 1A to the Criminal Procedure (Insanity) Act 1964.

  3. Absolute Discharge.

Release of those sentenced to a Hospital Order

Where the Crown Court makes a hospital order it may also make an order restricting the discharge of the offender from hospital, if it considers that it is necessary for the protection of the public from serious harm.


The court will have regard to the nature of the offence, the antecedents of the offender and the risk of his committing further offences if released.


The court can order that the offender be subject to special restrictions either with or without limit of time.


Release from Hospital

A patient may be released from Hospital by a Mental Health Review Tribunal, an independent panel comprising a judge, a psychiatrist and a lay person.


Case study, Michael Abram

Michael Abram aged 36, a schizophrenic from Merseyside, was released 19 months after he was detained for stabbing Beatle George Harrison, in December 1999.

He was acquitted at Oxford Crown Court of attempted murder on the grounds of insanity, but ordered to be detained at a secure hospital "without time restriction".

A tribunal ruled that he had responded well to treatment and was fit to be released into a "structured care environment". With medication he could lead a normal life.

Abram had been released from another hospital 5 months before the attack, he claimed doctors had failed to diagnose his illness.

Harrison's widow Olivia believed that the attack had robbed Harrison of the vital energy he needed to maintain his health, he died from cancer.


Powers of the Secretary of State to release patients

The Secretary of State has the authority under the Mental Health Act 1983 to vary a hospital order.  The Act authorise him to release patients either unconditionally or with restrictions, discharge him, return him to prison or release him on licence, (more options are shown below).


Actus reus

Rule 1:

It is up to the defendant to prove his own insanity. 


The "reverse standard" of proof.

The standard of proof is on the balance of probabilities.


Rule 2: Disease of the mind

Legal not medical


Disease of the mind is a legal not a medical question and not necessarily related to madness in a medical sense.  In practice, this is supported by medical evidence.


Any disease, which affects the functioning of the mind, is a disease of the mind.


Lord Denning in Bratty:

“Any mental disorder which has manifested itself in violence and is prone to recur is a disease of the mind.”


Lord Lane in Burgess: requirement that it is prone to recur..

Rule 3: The nature and quality of the act

Kemp (1957)
The court found the defendant not guilty by reason of insanity when he was unaware of his actions during a "blackout" caused by a disease of the body that affected the mind.


Means physical nature and consequences, not moral quality, of the act

R v Codere (1916) cutting his wife’s throat thinking it was a loaf of bread.


Lord Reading CJ said that the test is whether the act is right or wrong according to the standard accepted by reasonable men.


''He did not know what he was doing'' would apply if the accused was unconscious or, as in an example by Lord Denning in another context, that D thought he was throwing a log rather than the baby on the fire. The accused would have a defence of automatism or lack of mens rea.


Mens rea

Rule 4: “..did not know what he was doing was wrong”

The only ‘rule’ going to mens rea but in reality it adds very little to the other rules.

Legally not morally wrong.

R v Windle (1952)  ‘Wrong' in this context has been interpreted to mean legally as opposed to morally wrong.

“I suppose they will hang me for this.”…

 and they did.


Defect of reason

R v Clarke (1972)

Defect of reason does not include absentmindedness.
It means being deprived of the power to reason not just failing to use it.


Examples of medical conditions that have been held to give rise to "insanity"


R v Hennessy (1989)

  • If caused by hyperglycaemia (high sugar level caused by not taking insulin) is internal and therefore insanity.

  • If caused by hypoglycaemia (low sugar level in the blood, caused by taking insulin – and probably not eating or drinking alcohol) will amount to an external cause and therefore not insanity. 


R v Kemp (1957)


R v Burgess (1991)


R v Sullivan (1984)

R v Rabey (1977)

A Canadian case; it was held that a 'disassociative state' resulting from

'... the ordinary stresses and disappointments of life which are the common lot of mankind ...'

did not amount to an external cause.

It follows that evidence of such a 'disassociative state' would indicate a disease of the mind.


R v T (1990)

Evidence of a disassociative state resulting from something qualitatively different to the ordinary stresses of life, for example a rape attack, would indicate an external cause.  But in this case the jury still convicted.


R v Quick (1973) & R v Sullivan (1984)

A malfunctioning of the mind is not a disease of the mind if it is caused by some external factor such as a blow to the head or the consumption of alcohol or drugs This may amount to non-insane automatism.


Director of Public Prosecutions v Harper (1997)

Insanity is only a valid defence to an offence requiring guilty intent. Driving with excess alcohol is not such an offence.

State of mind not relevant

R v Grant (2001) provocation fell clearly within mens rea, but it can be understood from R v Antoine that accident, mistake and self-defence, could be considered under s 4A even though such defences almost invariably involved some consideration of the mental state of the defendant.



Since Woolmington, the onus lies on the prosecution to establish mens rea beyond all reasonable doubt, in all cases other than insanity or where it is laid down by statute, e.g. diminished responsibility in murder.


In the case of insanity, anomalously, the burden is on the defence to prove insanity on a balance of probabilities.


This has given rise to difficult and indeed somewhat absurd situations where the issues of insanity and automatism have arisen on the same facts.

Referring old cases

The Criminal Cases Review (Insanity) Act 1999 enables the Criminal Cases Review Commission to refer to the Court of Appeal a verdict of "guilty but insane" under the Trial of Lunatics Act 1883 and gives the Court of Appeal powers to hear and dispose of an appeal on such a reference.


Although the verdict of "guilty but insane" was abolished in the 1960s there may still be a small number of people who were the subject of such a verdict and would like to have it reconsidered by the Court of Appeal.


Information to victims

The Domestic Violence, Crime and Victims Act 2004 puts the onus on various parties to inform victims when there are changes relating to mentally disordered person including his release.


Insanity statistics

The latest available statistics were published in December 2007.

The number of hospital orders made because a defendant was found "not guilty by reason of insanity" were:-

























Disposals and discharges

The Mental Health Act 1983 provides for:-

  • the removal of a restriction order by the Secretary of State either
    conditionally or absolutely so that the hospital order continues
    unrestricted (section 42(1));

  • the discharge of a patient with a restriction order, either conditionally or
    absolutely, by the Secretary of State, and the termination of the
    restriction order where discharge is absolute (section 42(2));

  • the return to Prison Service establishments of sentenced prisoners
    (section 50(1)a);

  • the release of sentenced prisoners on licence (section 50(1)b);

  • the release of sentenced prisoners on completion of sentence (sections
    50(2) & 50(4));

  • the return of unsentenced prisoners to a Prison Service establishment
    to await court action where the Secretary of State or the court is
    satisfied that they no longer require treatment or no effective treatment
    is available (sections 51(3) & (4) respectively);

  • the transfer direction ceases to have effect in respect of untried
    prisoners at the end of their remand period, unless they are subject to
    further remand or committal for trial (section 52(2));

  • the direction or recommendation by a Mental Health Review Tribunal,
    of the discharge of a patient either conditionally or absolutely (sections

Insanity in need for reform

The modern applicability of the M’Naghten Rules arose for consideration in R v Johnson [2007] CA (whole case here).


The Court observed that they had to be approached with some caution as they had been formulated by the judges without the benefit of argument from counsel as the answers to a series of questions posed by the House of Lords.


There was a conflict between the English decision in R v Windle [1952] CA and the Australian decision in R v Stapleton (1952) as to whether the defendant had to know his act was legally or morally wrong.


Windle had never been doubted in England and had to be followed but the area was one which was notorious for debate. There was room for reconsideration of rules which had their genesis in the early years of the nineteenth century.


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