Boundary Commissions (United Kingdom) - Considerations and Process

Considerations and Process

The Boundary Commissions are required to apply a series of rules when designing constituencies.

Firstly, each proposed constituency has to comply with 2 numerical limits:

• the electorate of each constituency must be within 5% of the United Kingdom electoral quota. This number is the total mainland electorate divided by the number of mainland constituencies, which is 596. In simple terms, it is the average electorate of a mainland constituency.
• the area of a constituency must be no more than 13,000 square kilometres.

There are a small number of exceptions to the numerical limit on electorate which are specified in the legislation:

• the four protected island constituencies mentioned above are each permitted to have a smaller electorate than the usual limit;
• a constituency with an area of more than 12,000 square kilometres may have a smaller electorate than the usual limit; and
• constituencies in Northern Ireland may be subject to slightly different limits under certain circumstances.

Having satisfied the electorate and area requirements, each Commission can also take into account a number of other factors:

• "special geographical considerations" including the size, shape and accessibility of a constituency;
• local government boundaries;
• boundaries of existing constituencies;
• local ties which would be broken by changes to constituencies;
• inconveniences resulting from changes to constituencies.

It is obvious that the other factors are to an extent mutually contradictory, and therefore each Commission has discretion on how it applies them. In doing so, each Commission aims for a consistent approach within a review.

When a Commission publishes its proposals for public consultation, the consultation period is specified in the legislation:

• for Initial Proposals, a 12 week initial consultation period including a number of Public Hearings which offered an opportunity to give views orally;
• after the Initial Proposals, a 4 week secondary consultation allowing scrutiny of all comments submitted during the initial consultation; and
• for Revised Proposals, an 8 week consultation period.

It has been normal practice for local government electoral wards to be used as building blocks for constituencies, although there is no legislative requirement to do so. In Scotland, the introduction of multi-member wards in 2007 has made it harder to do so, since these wards each have a large electorate, and therefore a collection of complete wards may not give an electorate that is close to the required average.

The law specifies that the electorate used during a review is the registered electorate at the time of the start of the review, and not the electorate at the end of a review, or the total population.

Boundary changes can have a significant effect on the results of elections, but Boundary Commissions do not take any account of voting patterns in their deliberations, or consider what the effect of their recommendations on the outcome of an election will be.