The Rules
Paragraph 7 sets out the rules which the Commission are required by paragraph 3(2)(b) to give effect to when considering whether or not to recommend any alteration in any region or in the number of seats for a region. These rules are intended to ensure that:
no constituency falls within more than one region;
the regional electorate of a region is more or less the same as that in each of the other regions (allowing for differences in geography);
so far as reasonably practicable, the ratio of regional seats to constituency seats remains constant at 56 to 73, which was the ratio at the first election to the Parliament. Thus, if there was a reduction in the number of constituency seats in the Parliament (as a result of a reduction in the number of UK Parliamentary constituencies in Scotland), this should lead to a reduction in the number of regional seats so as to ensure, so far as reasonably practicable, that the same balance is maintained between constituency and regional members;
a region will have approximately the same number of regional seats as each of the other regions. If the number of regional seats cannot be divided exactly by eight, paragraphs 7 and 8 provide for the distribution of the residual seats among the regions with the larger regional electorates.
Paragraph 8 defines “the regional electorate” for the purposes of any report prepared by the Boundary Commission in relation to an electoral region. It is the number of persons whose names appear, on the enumeration date, on the registers of local government electors and who are registered for that purpose at an address within any Parliament constituency within a region. The enumeration date is the date on which the Boundary Commission published a notice of intention to make a report under section 5(1) of the Parliamentary Constituencies Act 1986.