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Revised proposals for new Parliamentary constituency boundaries in the Yorkshire and the Humber region

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2 Background to the 2023 Review

2.1 We are currently conducting a review of Parliamentary constituency boundaries on the basis of rules most recently updated by Parliament in 2020.4 These rules require us to make the number of electors in each constituency more equal. This report covers only the work of the Boundary Commission for England (there are separate Commissions for Northern Ireland, Scotland, and Wales) and, in particular, introduces our revised proposals for Yorkshire and the Humber.

2.2 Parliamentary boundaries are important, as they define the area in which voters will elect a Member of Parliament. When our recommendations are accepted, they are then used for the first time at the next General Election following their acceptance.

2.3 The legislation states that there will be 650 Parliamentary constituencies covering the UK – the same as the current number, but a statutory formula now distributes that total proportionately across the four parts of the UK. England has therefore been allocated 543 constituencies for the 2023 Review, ten more than there are currently. There are also other rules that the Commission has regard to when conducting the review – a full set of the rules can be found in our Guide to the 2023 Review5, but they are also summarised later in this chapter. Most significantly, the rules require every constituency we recommend to contain no fewer than 69,724 electors and no more than 77,062.

2.4 This is a significant change to the old rules under which Parliamentary boundary reviews took place, in which achieving as close to the average number of electors in each constituency was an aim, but there was no statutory fixed minimum and maximum number of electors. This, together with the passage of time since constituencies were last updated (based on data from 2000), means that in England, existing constituencies currently range from 53,210 to 109,246 electors. Achieving a more even distribution of electors in every constituency across England, together with the increase in the total allocation of constituencies, means that a significant amount of change to the existing map of constituencies is inevitable.

2.5 When implemented, the final recommendations that we will make will be the first set of boundaries to be defined under the new rules. While there has to be a significant amount of change across the country, we have, where practicable, attempted to limit the extent of such change, having regard to the statutory factors and the need to create the best possible pattern for constituencies as a whole. Under the legislation, we have a challenging job in conducting a review of constituency boundaries that is necessarily going to result, in many places, in constituencies that are unfamiliar to the public. Nevertheless, we have conducted the review in a rigorous and thorough fashion.

2.6 The revised proposals that we set out in this report, and in the reports for the other eight regions across England, are made on the basis of the evidence we received during two consultation exercises relating to our initial proposals, the careful consideration of that evidence by the Secretariat and our Assistant Commissioners, and the best judgement of the three Commissioners. We are confident that these revised proposals strike the best balance between the statutory factors and, having consulted twice already, we are close to settling on a final pattern of constituencies to recommend to Parliament next year. There are areas across the country where our judgement has been a balanced and marginal one between competing alternatives, and in such cases we have made clear that we are particularly looking for further evidence before we finalise our recommendations. In many other areas we are persuaded by the evidence we have received thus far, and we would therefore require new and significantly stronger arguments to make us depart from our revised proposals. If it exists, such new and compelling evidence would be welcome, but we will not be assisted by a repetition of arguments that have already been made, and which we have already considered. The requirement to keep constituencies within the permitted range of electors is strict, but otherwise we have sought to balance often conflicting considerations. Our proposals must also be comprehensive. We are acutely aware that very often a change that may seem obvious to make in one constituency necessarily requires far less attractive alterations in one or more neighbouring constituencies, and sometimes the consequential alterations reverberate through a whole chain of constituencies.

2.7 Our Guide to the 2023 Review contains further detailed background information, and explains all of the policies and procedures that we are following in conducting the review. We encourage anyone wishing to respond to the review to read this document, which will give them a greater understanding of the rules and constraints placed on the Commission, especially if they are intending to comment on our revised proposals and/or make their own counter-proposals.

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The rules in the legislation

2.8 As well as the primary rule that constituencies must have no fewer than 69,724 electors and no more than 77,062, the legislation also states that, when deciding on boundaries, the Commission may take into account:

    • special geographical considerations, including in particular the size, shape and accessibility of a constituency;
    • local government boundaries which existed, or were prospective, on 1 December 2020;
    • boundaries of existing constituencies;
    • any local ties that would be broken by changes in constituencies; and
    • the inconveniences attendant on such changes.

2.9 In relation to local government boundaries in particular, it should be noted that for a given area, where we choose to take account of local government boundaries, if there are prospective boundaries (as at 1 December 2020), it is those, rather than existing boundaries, of which account may be taken. This is a significant change to the former legislation, which referred only to the local government boundaries as they actually existed on the relevant date.

2.10 Our initial proposals for Yorkshire and the Humber (and the accompanying maps) were therefore based on local government boundaries that existed, or – where relevant – were prospective, on 1 December 2020. Our revised proposals contained within this report continue to be based on those boundaries. Our Guide to the 2023 Review outlines further our policy on how, and to what extent, we take into account local government boundaries. We have used the existing and prospective wards as at 1 December 2020 of unitary authorities, and borough and district councils (in areas where there is also a county council) as the basic building blocks for our proposals.

2.11 In a number of existing constituencies, changes to local government wards since constituencies were last updated (in 2010) have resulted in the new ward effectively being split, between the constituency the old ward was wholly a part of, and at least one other existing constituency. As part of our proposals, we will by default seek to realign the boundaries of constituencies with up-to-date ward boundaries, thus reuniting wards that are currently divided between existing constituencies. In places where there has been only a minor change to a ward, this may see an existing constituency boundary change only very slightly, to realign with the new ward. However, where wards in an area have been changed more significantly, this may result in the area covered by the new ward becoming part of a different constituency than the one much of that area was in previously.

2.12 Although the 2023 Review of Parliamentary constituencies will inevitably result in significant change, we have also taken into account the boundaries of existing constituencies so far as we can. We tried to retain existing constituencies as part of our initial proposals wherever possible, as long as the other factors could also be satisfied. This, however, proved difficult. Our initial proposals retained just under 4% of the existing constituencies in Yorkshire and the Humber as wholly unchanged, and a further 24% changed only to realign with changed boundaries of their component wards.

2.13 Among the many arguments we heard in response to the consultations on our initial proposals was the need to have particular regard to this factor of the rules to which we work. While some respondents might put a higher value on retaining existing constituency boundaries over the other factors in the rules, the legislation does not give any of these precedence over another, and the Commission therefore considers that its task is to seek to strike the best balance of all the factors in each area, within the numerical constraints.

2.14 Our proposals are based on the nine English regions as defined in the legislation; a description of the extent of each region also appears in the Guide to the 2023 Review. This report relates to the Yorkshire and the Humber region. There are eight other separate reports containing our revised proposals for the other regions. At the very beginning of the 2023 Review we decided, in agreement with all the qualifying political parties, to use these regions as discrete areas within which to undertake our work. You can find more details in our Guide to the 2023 Review and on our website. We stated in our initial proposals report that, while this approach does not prevent anyone from making proposals to us that cross regional boundaries, very compelling reasons would need to be given to persuade us to depart from the region-based approach.

2.15 In response to the consultations on our initial proposals, we did not receive sufficient evidence across the country to suggest that we should depart from the regional approach to this review. Therefore, this report, and all other regional reports, continue to use the regional boundaries as the basis for proposals for constituencies.

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4 The Parliamentary Constituencies Act 2020, available at
5 Available at

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