In some areas, counties and districts form a two-tier administrative structure, while in others they are combined under a unitary authority. The current system is the result of incremental reform which has its origins in legislation enacted in 19.
They were formed either by non-metropolitan districts taking on county-level functions, or by counties taking on district-level functions.
In some cases, borders were altered or districts were combined during this reorganisation.
The regions vary greatly in their areas covered, populations and contributions to the national economy.
There was a failed attempt to create elected regional assemblies outside London in 2004 and since then the structures of regional governance (regional assemblies, regional development agencies and local authority leaders' boards) have been subject to review.
Subdivisions of England (as of 2010) that have a principal local authority: two-tier non-metropolitan counties and their non-metropolitan districts; metropolitan boroughs; unitary authorities; London boroughs; and the sui generis City of London and Isles of Scilly.
The subdivisions of England constitute a hierarchy of administrative divisions and non-administrative ceremonial areas.
From April 2011 there has been a formal upper-tier structure in Greater Manchester with the creation of the Greater Manchester Combined Authority.
The Greater London administrative area created in 1965 corresponds to the London region.
The ancient City of London forms a 33rd division and is governed by the City of London Corporation, a sui generis authority unlike any other in England The City of London, and the rest of Greater London, each form a ceremonial county.
The London borough councils and the City of London Corporation provide the majority of services, for example they are education authorities and co-ordinate waste management, whereas the Greater London Authority is responsible for the key strategic services of public transport, the police, economic development and emergency planning.
Politically, however, they are fully independent entities, unaffiliated with the council of their former county.