The term has no legal definition in the United Kingdom. An individual can nominate any other individual as their next-of-kin. There is no requirement for the nominated person to be a blood relative or spouse, although it is normally the case. Someone who has no close family (or who has little or no contact with their surviving family members) may decide to list someone outside their family as their next of kin, for instance a friend or a neighbour.
The nominated person must agree to the nomination, otherwise it is invalid. The status of next-of-kin confers no legal rights and has no special responsibilities, except as referred to below in the specific context of the Mental Health Act.
The status of next-of-kin does not in any way imply that they stand to inherit any of the individual's estate in the event of their death. The intestacy rules[3] stipulate who inherits automatically (in the absence of a will); an individual can make a will and nominate other persons. If a minor inherits (children inherit from parents even in the absence of a will),[3][4] then, until the child is 18 years of age, there is a "trust" imposed, which means that the executors or trustees of the will remain responsible for the assets until the child is 18.[5] The term "next of kin" should not be confused with parental responsibility.[6]
In the context of health care, patients are often asked to nominate a next-of-kin when registering with their general practitioner, or alternatively on admission to hospital. Hospitals will then notify the next-of-kin that the patient has been admitted or if there is any change in their condition. If the patient is unconscious or otherwise unable to state their next-of-kin, hospitals will usually list their nearest blood relative, though there are no specific rules. Doctors attempt to seek the views of the next-of-kin when considering decision making for unconscious patients or those who lack capacity. The next-of-kin has no power to make any decisions regarding medical care, only to advise, and can neither override the previously stated wishes of the patient nor prevent the medical team acting in what they consider to be the best interests of the patient.
Traditionally, unmarried partners (especially same sex ones) were often excluded by certain institutions, but this has changed in recent years due to the increase in cohabitation in the UK, and in diverse families, such as those formed by unmarried partners with children (47.6% of children were born outside marriage in 2012).[7] As a result of these social changes, the policy in most NHS trusts is to ask a person on their admission to hospital to nominate their next of kin formally.[8]
Powers similar to next-of-kin as defined in other jurisdictions can be explicitly delegated to another person using lasting power of attorney,[9] under the provisions of the Mental Capacity Act 2005[10] (note that this Act does not relate specifically to mental health and is largely unrelated to the Mental Health Act).