However, the Office for National Statistics uses the collective term 'unitary administration' to describe all local government areas which operate as unitary authorities.
This is distinct from the two-tier system of local government which still exists in most of England, where local government functions are divided between county councils (the upper tier) and district or borough councils.
For many years the description of the number of tiers in UK local government arrangements has routinely ignored any current or previous bodies at the lowest level of authorities elected by the voters within their area such as parish (in England and Wales) or community councils; such bodies do not exist or have not existed in all areas.
Northern Ireland is divided into eleven districts for local government purposes.
While the phrase "unitary authority" is not used in Scottish legislation (whether from the Scottish Parliament or the UK Parliament), the term can be encountered (used either descriptively or erroneously) in a few official publications[6] and in (usually erroneous) use by United Kingdom government departments.