What is Murder in Law?

Murder is the unlawful killing of a human being with malice aforethought. This is the ‘common law’ definition of murder – there is no statutory definition.

How is murder proved in law?

For an individual to have committed the offence of murder, there must be both the act (the actus reus) and the mental element of intention to kill or cause grievous bodily harm (mens rea).

Actus reus

To convict a defendant of murder, the following must be proved:

  • The victim must have been a ‘person in being’. This excludes a baby in the womb
  • The victim must have died: a person is legally dead, for the purpose of murder, once their brain stem is dead
  • The victim’s death must have been caused by the act (or omission) of the defendant. If the victim dies of disease, this is not murder

It must also be shown that the killing was unlawful. If someone is killed following an act of self-defence which was reasonable in the circumstances, the killing will not be treated as unlawful. Similarly, the police may lawfully kill a terrorist to prevent an act of terrorism being carried out; and a patient may die as a result of the withdrawal of life support without the doctors being guilty of unlawful killing.

Mens rea

It must also be proved beyond reasonable doubt that the defendant has the intention (‘malice aforethought’) to kill or to cause grievous bodily harm (GBH).

If an intention to cause GBH can be proved, this will be sufficient to prove the mental element of the offence. This means someone may be convicted of murder if the victim dies as a result of the defendant’s unlawful actions – even if they only intended to cause that person serious harm.

Sentencing for murder

There is a mandatory life sentence following a murder conviction under section 1(1) Murder (Abolition of Death Penalty) Act 1965. However, in practice this does not usually mean ‘life’ in practice because the courts have a certain amount of discretion as to the minimum term of years a defendant must serve in any given case. This period of years is called the ‘tariff’ period of the sentence. If the offence is of the most serious kind – a whole life term must be imposed.

The Criminal Justice Act 2003

The Criminal Justice Act 2003 introduced and created four broad categories for murder. For each category there is a starting point for the length of the sentence, and the judge has the power to reduce the length of the sentence as they see fit.

Category 1

This is the most serious category of murder. The direction to the court for anyone convicted of a category 1 murder and at least 21 years of age is that a life sentence should mean life – and a ‘whole life’ order is the starting point. The judges can reduce this if they have reasonable justification to do so.

If the offender is aged 18-20, the starting point would be 30 years and if under 18, the starting point is 12 years.

Category 2

Where the offender used a firearm or explosive, the starting point is 30 years if aged 18 or over, and 12 years for an offender aged under 18.

Category 3

In cases of murder where the offender brings, and uses a knife to commit murder, the starting point is 25 years for an offender aged 18 or over, and 12 years if under 18.

Category 4

For other cases, the starting point is 15 years for an offender aged at least 18 years, and 12 years if under 18

The sentencing is not intended to place a value on the life of the victim/s, rather it is to reflect the severity of the offender’s actions: the more serious the conduct, the longer the term in prison.

Article written by...
Lucy Trevelyan LLB
Lucy Trevelyan LLB

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Lucy graduated in law from the University of Greenwich, and is also an NCTJ trained journalist. A legal writer and editor with over 20 years' experience writing about the law.