The definition of murder comes from Sir Edward Coke in Institutes of the Lawes of England (1628):
“Murder is when a man of sound memory, and of the age of discretion, unlawfully killeth within any county of the realm any reasonable creature in rerum natura under the king’s peace, with malice aforethought, either expressed by the party or implied by law, [so as the party wounded, or hurt etc. die of the wound or hurt, etc. within a year and a day after the same].”
The first part deals with a person being of sound mind and therefore covers issues such as insanity under the M'Naghten (1843) rules as well as diminished responsibility under s. 2 of the Homicide Act 1957. The age of criminal responsibility in England and Wales is 10 years old.
Unlawfully killing excuse defendants who have a lawful excuse for their actions such as actin in self-defence.
Within any county has been greatly expanded to cover all murders committed by British citizens (s. 9 Offences Against the Person Act 1861; s. 3 British Nationality Act 1948) and can even cover non-British citizens under s. 4 Suppression of Terrorism Act 1978.
The victim must be in existence and this can be controversial in areas where the start of life is concerned. The foetus is not seen as being in existence and therefore falls under other offences such as under the Infant Life (Preservation) Act 1929. The baby must have independent existence and be fully expelled from the mother (Poulton (1832)) but does not necessarily have to have the umbilical cord cut yet (Reeves (1839)). Under Article 2 of the European Convention on Human Rights this issue is left to the states under the mar