Changes
In England review areas are usually based on local authority boundaries, usually ceremonial county boundaries, with Unitary Authorities only being regarded as separate review areas in special cases. York, for example, was split into two constituencies with no electoral wards from North Yorkshire.
Some areas of England were awarded extra constituencies in the review, including Lancashire, and the Essex review area. Other review areas have had one constituency removed, such as Tyne and Wear. Greater London as a whole was reviewed on borough-by-borough basis and lost two constituencies overall.
In Wales, the total number of seats remained at 40, although new seats were recommended by radical redrawing of boundaries in Clwyd and Gwynedd: Arfon and Dwyfor Meirionnydd replace Caernarfon and Meirionnydd Nant Conwy respectively; Aberconwy replaces Conwy. Currently Welsh constituencies have on average 16,000 fewer electors than their counterparts in England.
The Boundary Commission for Northern Ireland announced in 2006 that minor changes would take place in the east of the province to its existing constituencies.
In Scotland, the total number of seats dropped from 72 to 59. This was due to changes made by the Scotland Act 1998, applying the English electoral quota to Scotland. Unlike the other three countries, these changes took effect at the 2005 election. Three seats remained unchanged - East Renfrewshire (formerly named Eastwood), Orkney and Shetland, and Na h-Eileanan an Iar (formerly named Western Isles).
These changes were the first major changes in the composition of UK Parliamentary constituencies since 1997.
The list of constituencies used in the 2010 general election, including changed constituencies resulting from these reviews can be found at Constituencies in the United Kingdom general election, 2010. Note that the Scottish constituencies remained the same from the 2005 election.
One consequence of boundary reviews is the notional changing of representation of some constituencies where calculations of voting intentions suggest a party other than the victor at the last general election would have been successful had the boundaries been in place.
Read more about this topic: Fifth Periodic Review Of Westminster Constituencies