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Parliamentary Voting System and Constituencies Act 2011

Section 11: Number and distribution of seats

47.Section 11 replaces the rules under which the four Boundary Commissions make recommendations as to how their part of the UK should be divided into constituencies, which are currently set out in Schedule 2 to the 1986 Act. The section substitutes a new Schedule 2. Rule 1 of the new Schedule 2 sets the number of constituencies in the UK at 600. Rule 2 provides for there to be less variation in the size of the electorate in each constituency than at present: the electorate of each constituency is required to be within 5% either side of the UK electoral quota. The UK electoral quota is the number of people in the UK on the electoral register published two years and ten months before the date by which the Commissions’ reports are to be submitted less the electorate on that date of the protected constituencies named in Rule 6, divided by 596, i.e. the number of constituencies in the UK (600) less the four protected constituencies in rule 6.

48.Rules 3 and 8 prevent the Boundary Commissions from recommending constituencies that cross national borders and set out the procedure for calculating the number of constituencies which there are to be in each part of the UK. This is to be done by the Sainte-Laguë method. Under this method, the first constituency is allocated to the part of the UK with the largest electorate (that is to say, the part of the UK with the largest registered electorate). The next constituency and subsequent constituencies are allocated in the same way, except that the electorate of a part of the UK to which one or more constituencies have already been allocated is divided by twice the number of seats already allocated to that part of the UK plus one. If two (or more) parts of the UK are equally entitled to a seat (or seats), the seat is allocated to that nation, of those that are tied, with the smaller or smallest electorate. The preserved constituencies set out in Rule 6 and their electorates are not included in the allocation process.

49.Rule 4(1) imposes a geographical size limit for constituencies of 13,000 square kilometres. This means that the Boundary Commissions may not draw up a constituency which is significantly geographically larger than the current largest constituency. Rule 4(2) provides for an exemption from the lower parity target of 95% of the UK electoral quota for a constituency larger than 12,000 square kilometres, if a Boundary Commission is satisfied that it is not reasonably possible for the constituency to comply with the parity rule. This resolves the problem that might be faced by a Boundary Commission should it be unable to draw up a constituency that meets both the parity rule and the size limit in a sparsely populated area.

50.Rule 5 sets out factors which the Boundary Commissions may take into account in determining constituency boundaries (subject to their complying with the electoral parity rule and the rule about the maximum geographical size of constituencies). The factors are similar to those in the 1986 Act. They may consider special geographical considerations, such as the size, shape and accessibility of a constituency. The Commissions may also take account of local government boundaries, including those of wards. Because of the parity principle in rule 2 constituencies are likely to cross such boundaries more frequently than in the past, but where a Commission has two or more options for recommending how a constituency should be drawn, all of which adhere to the principle in rule 2, but only one of which would not involve crossing the boundary of a local government area, the rule would enable the Commission to recommend that option. As at present, the Commissions may consider local ties such as social, commercial, cultural and transport links that would be broken by changes in constituencies and, in the case of reviews after the first one following the passing of the Act, any inconveniences which would result from a boundary change. They may also take the boundaries of existing constituencies into account.

51.Rule 6 provides for the two Scottish island constituencies of Na h-Eileanan an Iar (the Western Isles) and Orkney and Shetland to be preserved, and for two constituencies on the Isle of Wight. The electorates of those four constituencies are to be removed from the UK electorate and the Scottish electorate (for Na h-Eileanan an Iar and Orkney and Shetland) and the English electorate (for the Isle of Wight) for the purposes of calculating the UK electoral quota.

52.Rule 7 makes provision to compensate for the potential impact of rules 3 and 8 on the average size of constituencies in Northern Ireland. Since the result of rule 3 is that a whole number of constituencies is allocated to each part of the UK (which is done as set out in rule 8), it will almost always be the case that the number of constituencies allocated to a part of the UK is very slightly higher or lower, by a fraction of a constituency, than its purely theoretical entitlement. This may have a consequential effect on the average size of a constituency in Northern Ireland which, because of the smaller electorate in Northern Ireland compared to other parts of the UK, might constrain the ability of the Boundary Commission for Northern Ireland (BCNI) to recommend constituencies within the parity principle in rule 2. Rule 7 therefore provides that if the difference between the Northern Ireland electorate and the UK electoral quota multiplied by the number of seats in Northern Ireland exceeds one third of the UK electoral quota, and in the opinion of the BCNI it would unreasonably impair their ability to take into account the factors set out in rule 5, or would make the preparation of their report so complex that they would be unable to comply with the deadline for the submission of their report in section 3(2) of the 1986 Act, then the BCNI may propose constituencies that vary from the upper or lower limits imposed by rule 2 by a fixed amount, being the difference between the UK electoral quota and the electorate of Northern Ireland as it exists on the review date divided by the number of seats allocated to Northern Ireland under rules 3 and 8.

53.Rule 9 is an interpretation provision.

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