England

• Greater London
• Metropolitan County
• Non - Metropolitan County
• Unitary Authority
• Metropolitan District
• Non - Metropolitan District
• London Borough/City of London
• Electoral ward/division
  (known as division in the Isle of Wight)

Wales

• Unitary Authority
• Electoral Division

Scotland

• Council Area
• Ward
  

Northern Ireland

• Local Government District
• District Electoral Area
• District Ward

UK

• NUTS areas 1-5

• Postal Areas
• Postal District
• Postal Section
• Unit Postcode
• Postal Address

Census 1991

• Enumeration Districts -
  England and Wales
• Output Areas -
  Scotland
• Wards and Enumeration Districts -
  Northern Ireland

European

• European Constituency

England

• Westminster Parlimentary Constituency
• Electoral Ward/Division

Wales

• Westminster Parlimentary Constituency
• Electoral Ward

Scotland

• Westminster Parlimentary Constituency
• Scottish Parliamentary Constituency
• Ward

Northern Ireland

• Westminster Parlimentary Constituency
• District Electoral Area
• District Ward

Census 2001

• Output Areas -
  England, Wales, Scotland and Northern Ireland