urrendered enemy combatant in time of war
- Executing a person in accordance with a legally imposed sentence of death
 Mitigating circumstances
Most countries allow conditions that "affect the balance of the mind" to be regarded as mitigating circumstances against murder. This means that a person may be found guilty of "manslaughter on the basis of diminished responsibility" rather than murder, if it can be proved that the killer was suffering from a condition that affected their judgement at the time. Depression, post-traumatic stress disorder and medication side-effects are examples of conditions that may be taken into account when assessing responsibility.
A somewhat different defense is insanity, which is almost exclusively used in cases of psychosis such as that caused by schizophrenia. In some jurisdictions, the verdict "not guilty by reason of insanity" is used in these cases, leading to the odd circumstance that a victim was murdered, but the killer is technically not a murderer under the law. Some countries, such as Canada, Italy, the United Kingdom and Australia, allow post-partum depression, or 'baby-blues', as a defense against murder of a child by a mother, provided that a child is less than a year old. Killers who have successfully argued the insanity defense are usually assigned mandatory clinical treatment for many years, rather than prison.
 Country-specific murder law
 United Kingdom
About 850 murders per year (reported in 2000) are committed in the United Kingdom. This is low compared to the United States with 12,000. These are only raw numbers which do not take varying populations into account: a better perspective can be gained by comparing murders per year per hundred thousand population (1 in the UK, 4 in the USA, and 63 in Colombia - source).
In English law, homicide can be divided into several offences, including:
- Murder - Killing of another person whilst having either the intention to kill (with "malice aforethought") or to cause grievous bodily harm.
- Manslaughter - Unintentional and unlawful killing of another person.
- Infanticide - Intentional killing of an infant under 1-year-old by a mother suffering from post-natal depression or other post-natal disturbance.
- Causing death by dangerous driving (of a motor vehicle).
The difference between murder and manslaughter is based on intent. English Law also allows for the transfer of intent. For example, in the circumstances where a man fires a shotgun with the intent to kill person A, or at least maim them but the shot misses and kills an otherwise unconnected person B then the intent to kill transfers from person A to person B and a charge of murder would stand.
Causing death by dangerous driving was introduced because of the perceived difficulty of persuading juries - many of whom were drivers - to convict on a charge of manslaughter.
Most common law jurisdictions, such as British Commonwealth countries, do not allow for the defense of necessity. For example, it is murder to kill another human being for food, even if without doing so one would die of starvation. This originated in a case of four shipwrecked sailors cast adrift off the coast of South Africa in the 1880s; two of the sailors conspired to kill one of the other sailors (a sick cabin boy), and having killed him ate his flesh to survive: R v Dudley and Stevens (1884) 14 QBD 273.
- See also Scottish Criminal Law for differences with English Law.
Canada has about 550 murders per year, a number that is fluctuating. This is equivalent to numbers in most of the western world, except the U.S. which has triple the number per capita. The main methods of murder in Canada are shootings (30%), stabbings (30%), and beatings (22%).
Canada has four types of crime that can be considered murder:
- first degree murder - the intentional killing of another person with premeditation, in the furtherance of another serious criminal offense (kidnapping, robbery, etc.), or the killing of a peace officer
- second degree murder - the intentional killing of another person without premeditation (ie killing in