The UK Government classifies bodies into four main types. The Scottish Government also has a fifth category- NHS bodies.
These bodies consist of boards which advise ministers on particular policy areas. They are often supported by a small secretariat from the parent department and any expenditure is paid for by that department.
These bodies usually deliver a particular public service and are overseen by a board rather than ministers. Appointments are made by ministers following the Code of Practice of the Commissioner for Public Appointments. They employ their own staff and are allocated their own budgets.
These bodies have jurisdiction in an area of the law. They are co-ordinated by the Tribunals Service, an executive agency of the Ministry of Justice, and supervised by the Administrative Justice and Tribunals Council, itself a NDPB sponsored by the Ministry of Justice.