Guardianship describes the legal authority and responsibility conferred on an individual (or, in some cases, a body) to make decisions and care for a child or an adult lacking capacity, where parental responsibility or ordinary decision‑making rights are insufficient or inappropriate. It commonly arises on the death, absence or incapacity of parents, or in adult incapacity regimes.In England and Wales, “guardian” and “guardianship” are principally governed by the Children Act 1989 and related legislation, focussing on parental responsibility for children. For adults, decision‑making is usually addressed through the Mental Capacity Act 2005 (deputies rather than “guardians”), save for limited statutory schemes.In Scotland, “guardianship orders” under the Adults with Incapacity (Scotland) Act 2000 are central to adult incapacity law, while child guardianship is tied to parental responsibilities and rights under the Children (Scotland) Act 1995.In Northern Ireland and Ireland, guardianship of children is mainly regulated by family law and children legislation, with adult incapacity addressed through separate frameworks (including enduring powers of attorney and capacity legislation).Across all jurisdictions, guardianship is a protective measure, scrutinised by the courts, with duties owed to the best interests and welfare of the child or protected adult.