The term "metropolitan borough" was first used for administrative subdivisions of the County of London between 1900 and 1965.

Metropolitan districts were local education authorities, and were also responsible for social services and libraries.

In 1986 the metropolitan county councils were abolished under the Local Government Act 1985 and most of their functions were devolved to the metropolitan boroughs, making them, to a large extent, unitary authorities in all but name.

At the same time some of the functions of the abolished metropolitan county councils were taken over by joint bodies such as passenger transport authorities, and joint fire, police and waste disposal authorities.

They are the principal local authorities in the six metropolitan counties and are responsible for running most local services, such as schools, social services, waste collection, and roads.