New Constituency Boundaries for Britain 2013

This page first posted 18 September 2011

Following the passage of the Parliamentary Voting System and Constituencies Act, the four national Boundary Commissions were asked to undertake the "Sixth Periodic Review" of contituency boundaries to equalise the size of seat both within and between the four nations of the UK.

In October 2012, the Boundary Commission for England published their revised recommendations for the new constituencies boundaries, following their initial proposals in September 2011. These new boundaries were originally intended to come into force for 2015, but this has been cancelled by the new Electoral Registration and Administration Act 2013. These boundaries will not be used for any election, and are presented here for academic interest. A completely new review of boundaries will be initiated after the next general election and will be finalised by October 2018.

Our thanks go to the Boundary Commission for making the full ward details available to Electoral Calculus.

In September 2012, the Boundary Commission for Scotland published their revised recommendations for Scotland, after their initial proposals of October 2011. This reduces the number of Scottish seats from 59 to 52. The Boundary Commission for Wales published their initial recommendations in January 2012 and revised proposals in October 2012. The number of Welsh seats decreased from 40 to 30. The Boundary Commission for Northern Ireland published their initial recommendations in September 2011 and revised proposals in October 2012. They decreased the number of Northern Irish seats from 18 to 16.

We have calculated implied results for the 2010 election as if it had been run under the revised new boundaries. All of the UK results are now based on local authority election results, which is the most accurate way of calculating them. Details of the calculation method are available.

The new boundaries would have changed the overall result of the 2010 General Election from "Conservatives short 19 seats of a majority" to "Conservatives short 1 seat of a majority".

The implied results for 2010 under the new boundaries can be seen in both web-style and flat-file formats:

• Browsable England web-style page (415k).
• Browsable Wales web-style page (28k).
• Browsable Scotland web-style page (48k).
• Browsable Northern Ireland web-style page (16k).
• A flat-format text file (44k). Format details are in the historical data section.

Changes in numbers of seats

These boundary changes result in a gain of twelve seats to the coalition government's parliamentary majority. This includes all the new seats across all the UK (England, Scotland, Wales and Northern Ireland).

Disappearing Seats

Seats changing hands

Newly created seats

History of revisions.

• 17 September 2011 Initial version.
• 13 November 2011 Scottish boundaries and implied Scottish results published
• 27 November 2011 All Scottish seats and some English seats now based on local election results.
• 18 December 2011 North London seats now based on local election results. Three seats (Ealing, Paddington, Willesden) now predicted to be held by their incumbents.
• 23 December 2011 South London seats now based on local election results. Clapham Common now predicted CON; Sutton and Cheam now predicted CON.
• 2 January 2012 Northern and Central England now based on local election results. Eleven seats predicted with different winners.
• 11 January 2012 Southern England now based on local election results. Somerset NE now predicted LIB. England now complete.
• 14 January 2012 Wales implied results published, fully based on local election results. GB now complete.
• 22 January 2012 Northern Ireland implied results published, using simple method.
• 28 January 2012 Northern Ireland results now based on local election results. Belfast North and Belfast South East now predicted to be held by incumbents. UK complete for Boundary Commissions' initial proposals.
• 21 October 2012 England and Scotland updated to reflect the revised proposals from their Boundary Commissioners.
• 17 November 2012 Wales updates to reflect revised Boundary Commission proposals.
• 31 March 2013 Northern Ireland updates to reflect revised Boundary Commission proposals.
• 8 September 2016 Remove Stirling and Yorkshire East from list of disappearing seats (error correction)