Fifth periodic review of Westminster constituencies

The fifth periodic review of Westminster constituencies was undertaken between 2000 and 2007 by the four boundary commissions for England, Scotland, Wales and Northern Ireland for the UK Parliament.

The post-2010 shape of those for the rest of the UK can be viewed alongside those for Scotland of 2005 at United Kingdom Parliament constituencies.

A side effect of reviews is the number of seats won by each party may change (even if all voters repeated their votes at later elections).

In Northern Ireland, the Boundary Commission recommended that the number of seats remained at 18, with minor changes to 12 of these, primarily in the east of the province.

In England, the seats recommended seldom straddle the largest council areas, i.e. counties (metropolitan or otherwise); however they may cross boundaries of unitary authorities.

The Boundary Commission for England created one extra seat each to represent ten non-metropolitan counties: Cornwall, Derbyshire, Devon, Essex, Hampshire, Lancashire, Norfolk, Northamptonshire, Warwickshire and Wiltshire; and one covering the area of the former county of Avon.

This solution ensures that the sizes of the electorates are not too disparate, in other words, quite fairly apportioned to reflect the adult resident population.

As a result of changes to the names of seats, it is not always easy to clearly identify newly created constituencies or those abolished during the review process.

A majority of these involved significant changes resulting from the knock-on impact of new or abolished seats within review areas.

Aberdeenshire Central Dundee Perth and Kinross West Lothian Borders Dumfries and Galloway / South Lanarkshire North Lanarkshire North Ayrshire / South Ayrshire Shetland Islands Shetland Islands