Parliamentary boundary reviews: details of how they will be run

General provisions for the Parliamentary boundary reviews

Across the UK, the number of constituencies is being reduced from 650 to 600, with similar reductions in each part of the UK: England 502 in place of the current 533; Wales 30 in place of the current 40; and Northern Ireland 16 in place of the current 18.

These numbers come from allocating constituencies in proportion to the electorate of each of the four parts of the United Kingdom, using the Sainte-Laguë method. The two Scottish island constituencies and the two Isle of Wight constituencies are not included in the constituency allocation process.

The electoral quota for the review, which is the average electorate per constituency across the UK, is 76,641, with the electorate of each constituency having therefore to be within the range 72,810 to 80,473. Special exemption from these rules are made for two Scottish island constituencies, Na h-Eileanan an Iar (the Western Isles) and Orkney and Shetland, two Isle of Wight constituencies and also for very sparsely populated areas if constituencies would have to be larger than 12,000 square kilometres.

The reviews are being carried out following the Parliamentary Voting System and Constituencies Act 2011. There is a separate Boundary Commission for each of England, Scotland, Wales and Northern Ireland, further information from each of which are in the sections below.

The standard study of the Parliamentary Boundary Commissions and how they and their rules have worked in the past is The Boundary Commissions: Redrawing the UK’s Map of Parliamentary Constituencies.

For the Liberal Democrats, the Boundary Review submissions are being coordinated by the regional parties (in England) and by the Welsh and Scottish state parties. I am also helping with this process, so you can also get in touch with me direct if you have any queries.


This table shows the electorate for each region in England, the existing number of Parliamentary constituencies in each and the number of constituencies the Parliamentary Boundary Commission for England proposes to allocate to each:

RegionElectorateExisting allocationProposed Allocation
East Midlands3,361,0894644
North East1,971,2492926
North West5,253,0197568
South East6,192,504*8481**
South West4,042,4755553
West Midlands4,115,6685954
Yorkshire and the Humber3,848,9425450

*after deduction of the electorate (110,924) of the Isle of Wight

**Does not include the two Isle of Wight constituencies

One of the English Parliamentary Boundary Commission’s newsletter includes this important information:

The Commission first adopted its policy of using wards as the basic building block for constituencies at the third general review (1976-1983) and it continued with this policy at both the fourth (1991-1995) and fifth (2000-2006) general reviews, where no ward was divided between constituencies. In considering its policies for the 2013 Review, the Commission has decided that it would be desirable, once again, to use whole wards to create constituencies where it is feasible to do so, having regard to the 5% statutory requirement.

Using wards will allow the Commission to benefit from the considerable information that is already available about them. The composition and the area of each ward is clearly defined in a Statutory Instrument, and the electoral statistics for each are available from the Electoral Registration Officers for the districts in which they are located.

The Commission’s experience from previous reviews also confirmed that any division of a ward between constituencies would be likely to break local ties, disrupt political party organisations, cause difficulties for Electoral Registration and Returning Officers and, possibly, cause confusion to the electorate.

Although work has been undertaken to look at different potential building blocks (such as post code areas) that comply with the statutory criteria, which might be used in the future for mapping constituencies, at the moment there is no sufficiently reliable alternative for which both a full set of digital mapping and electoral statistics exist, which is available for use in the 2013 Review.

In those instances where it does not prove feasible to meet the statutory 5% electoral parity requirement using whole wards, or in other exceptional and compelling circumstances having regard to the specific factors identified in rule 5 in Schedule 2 to the 1986 Act, the Commission is prepared to divide wards between constituencies to the extent necessary to meet that requirement or to make allowance for such circumstances. If such situations were to arise, the Commission has decided that it would divide a ward into polling districts (which are determined by local authorities), as the electorates for these units can be calculated from the published electoral registers and it should be possible to obtain paper mapping for them from Ordnance Survey, with the assistance of the relevant Electoral Registration Officers.

It is also going to consult on the use of European regional boundaries in England:

In light of the new requirement to allocate a fixed number of constituencies to England and to ensure a manageable and readily comprehensible general framework within which the detailed mapping of constituencies can proceed in an orderly way, the Commission is minded to use the electoral regions, which are already defined in legislation for the purposes of European elections, as a template for grouping and allocating the 500 constituencies across England (other than the Isle of Wight).

The reason the Commission favours adopting an approach based on an initial allocation of constituencies on a regional basis, subject to any representations to be received, is that this appears to be the most appropriate way in which the Commission could fulfil the task which it has been given by Parliament. The Commission considers that adopting this process will enable it best to meet the statutory requirement to allocate a precise number of constituencies to England which all satisfy the statutory 5% electoral parity requirement (subject to the exception made for the two constituencies to be allocated to the Isle of Wight). It seems to the Commission that such a process will allow that objective to be achieved in a way which best affords recognition to regional and local affiliations while at the same time making its task manageable within the statutory timetable (since this general approach will limit the number of permutations and combinations of wards and, as necessary, polling districts which need to be considered in order to comply with the new statutory requirements).

UPDATE: The Boundary Commission for England has now confirmed it is going to use European Parliament regions in this way.

Other information about the English Parliamentary boundary review:



The Welsh Parliamentary Boundary Commission says (in its news release):

Following some preliminary modelling work, the Commission has concluded that implementing the new statutory framework is likely to require very extensive and wide-ranging changes to be made to the existing pattern and composition of constituencies.

Other information about the Welsh Parliamentary boundary review:

Northern Ireland

The Boundary Commission for Northern Ireland says:

The next step in the process will be the publication of provisional recommendations in respect of the new constituencies in the latter part of 2011 to be followed by a period of public consultation which will include a series of public hearings.

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