This is basically a common-law offence and to constitute it there must be an unlawful killing of another human being under the Queen’s peace with malice aforethought. Formerly, the victim had to die within a year and a day of the defendant’s criminal conduct.
The year and a day rule prevented the prosecution of defendants for murder as medical science developed techniques for keeping seriously injured persons alive for long periods.
The Law Reform (Year and a Day Rule) Act 1996 abolished the year and a day rule, i.e. the irrebuttable presumption that applied for the purposes of offences causing death where more than a year and a day had elapsed. The Act abolishes the rule in regard to murder, manslaughter, abetting suicides, infanticides, causing death by dangerous driving when under the influence of drink, and aggravated vehicle taking causing death (s.1). It does not affect the application of the rule to acts or omissions occurring before the relevant part of the Act came into force, i.e. 17 June 1996 (s.3).
Section 2 restricts the bringing of proceedings in that the consent of the Attorney-General is required before a prosecution can be brought in cases where the injury alleged to have caused the death did in fact occur more than three years before the death and also where the person to be prosecuted for a fatal offence has already been convicted of an offence, e.g. grievous bodily harm, connected to the circumstances of the death.
Since the killing must be of a human being, the unlawful killing of an unborn child is not murder. However, such killings are covered and made criminal in appropriate circumstances by s.58 of the Offences against the Person Act 1861, s.1 of the Infant Life (Preservation) Act 1929 and the Abortion Act 1967. The detail of these offences is not considered here. The expression ‘another human being’ includes a child that has been born alive and has an existence independent of the mother. Where a person injures a child while it is in its mother’s womb and it dies later from those injuries after being born, it may be appropriate to bring a charge of murder (see Attorney-General’s Reference (No 3 of 1994)  3 All ER 936 House of Lords). The fact that the victim must be ‘under the Queen’s peace’ prevents the killing of the enemy in wartime from being murder. This refers to killing in action. It is murder to kill prisoners of war. Under the Offences against the Person Act 1861 any British citizen who commits murder anywhere in the world may be tried in England or Wales. In addition, a killing in self-defence may be lawful and so not murder (see further Chapter 30).
Some consideration has already been given to this. However, the mens rea for murder is defined as ‘malice aforethought’. According to the House of Lords in Maloney (1985), murder is a crime which requires a specific intent, either direct as where the defendant desired the consequences, or oblique as where he foresaw the consequences as near certain. Recklessness is not enough. The court must be satisfied of the presence of such an intent either to kill or cause grievous bodily harm.
In this connection, it should be noted that the decision in Maloney (1985) confirms that it is enough malice if the intention is not to kill but to cause grievous bodily harm.
Maloney thus decides that intent to kill and intention to cause grievous bodily harm are the only forms of mens rea for murder.
In so far as the expression ‘malice aforethought’ suggests evidence of premeditation or plot, it is misleading since this is not necessary, provided the specific intent to kill is present.
Manslaughter is divided into voluntary manslaughter and involuntary manslaughter.
This is murder reduced to manslaughter by the presence under the Homicide Act 1957 of provocation, diminished responsibility or suicide pact. Once it is shown that one of these partial defences exists, the crime ceases to be murder and the fixed penalty of life imprisonment goes, giving the judge discretion as to sentence.
The mens rea is, therefore, the mens rea for murder, but with the mitigating factors of provocation, diminished responsibility or suicide pact.
Section 3 of the Homicide Act 1957 applies. It provides as follows.
Where on a charge of murder there is evidence on which the jury can find that the person charged was provoked (whether by things done or by things said or by both together) to lose his self control, the question whether the provocation was enough to make a reasonable man do as he did shall be left to be determined by the jury; and in determining that question the jury shall take into account everything both done and said according to the effect which, in their opinion, it would have on a reasonable man.
By reason of s.2(1) of the Homicide Act 1957 this defence is available in respect of a murder charge only. The burden of proof is 011 the defence which must how that the defendant ‘was suffering from such abnormality of mind (whether arising from a condition of arrested or retarded development of mind or any inherent causes or induced by disease or injury) as substantially impaired his mental responsibility for his acts and omissions in doing or being a party to the killing’.
Lord Parker in R v Byrne  2 QB 396, 403 (CA) stated that abnormality of mind means:
a state of mind so different from that of ordinary human beings that the reasonable man would term it abnormal. It appears to us to be wide enough to cover the mind’s activities in all its aspects, not only the perception of physical acts and matters and the ability to form a rational judgment whether an act is right or wrong, but also the ability to exercise will power to control physical acts in accordance with that rational judgment.
The question whether the requirement that the defence must prove diminished responsibility in terms of Art 6 of the Human Rights Convention (right to a fair hearing) was raised in R v Lambert 1 All ER 1014. The Court of Appeal ruled that this burden of proof was not contrary to Art 6. The presumption of innocence still applied. This was a special defence and did not interfere with the general rule that the burden of proof is on the prosecution.
The defence is wider than that of insanity and covers other mental conditions. In fact the defendant may know what he is doing and that it is wrong. His alleged problem is that he finds it substantially more difficult to control his actions than would a normal person, and this difficulty is caused by some abnormality of his mind.
The Homicide Act 1957 states in s 4(1) that:
It shall be manslaughter and not murder, for a person acting in pursuance of a suicide pact between him and another to kill the other or be a party to the other being killed by a third person.
The defendant must show:
A suicide pact is defined by the Homicide Act 1957 in s.4(3) as:
A common agreement between two or more persons having for its object the death of all of them, whether or not each is to take his own life, but nothing being done by a person who enters into a suicide pact shall be treated as done by him in pursuance of the pact unless it is done while he has a settled intention of dying in pursuance of the pact.
It is apparent from the case law that involuntary manslaughter is based upon either an unlawful act resulting in death, sometimes called constructive manslaughter, or death resulting from gross (or criminal ) negligence
Constructive manslaughter has three ingredients as follows:
In R v Dawson  81 Cr App R 150 a petrol station attendant with a weak heart died of heart failure when the appellant attempted a robbery of the station. In judging whether this act was sufficiently dangerous, the Court of Appeal applied a test based on the ‘sober and reasonable’ bystander who could be assumed to know that the use of a replica gun was likely to terrify people and so be a danger to those with a weak heart.
To cause death by any lack of due care will not amount to manslaughter. A very high degree of negligence is necessary for the establishment of a crime. Whether the appropriate degree of negligence exists is a matter for the jury, following direction by the judge. The test according to the House of Lords in R v Adomaho  3 All ER 79 is that a defendant is properly convicted of involuntary manslaughter by breach of duty if the jury is directed and finds that the defendant was in breach of a duty of care toward the victim who died, that the breach of duty caused the death of the victim and that the breach of duty was such as to be characterised as gross negligence and, therefore, a crime. Lord Mackay LC said, giving an analysis of the law:
in my opinion the ordinary principles of the law of negligence apply to ascertain whether or not the defendant has been in breach of a duty of care towards the victim who has died. If such breach of duty is established the next question is whether that breach of duty should be characterised as gross negligence and therefore as a crime. This will depend on the seriousness of the breach of duty committed by the defendant in all the circumstances in which the defendant was placed when it occurred. The jury will have to consider whether the extent to which the defendant’s conduct departed from the proper standard of care incumbent upon him, involving as it must have done a risk of death to the patient, was such that it should be judged criminal.
The circumstances to which a charge of involuntary manslaughter may apply are so various that it is unwise to attempt to categorise or detail specimen directions, but certainly civil liability, although sufficient to establish the duty of care, is not sufficient to amount to ‘gross negligence’, nor is Caldwell recklessness. The test as stated in Adomako is enough. In the case the defendant was an anaesthetist during an eye operation on a patient. A tube supplying oxygen to the patient became disconnected but the defendant failed to notice this for some six minutes. The patient suffered cardiac arrest and died. The defendant was convicted of manslaughter and his appeal to the House of Lords was dismissed. There would, of course, have been an action in negligence as a fatal accident but it is interesting to note that, because the negligence here is gross, criminal liability can also result.