Proposals for new parliamentary constituencies have now been published by three of the four UK Boundary Commissions. Ron Johnston examines the nature of those recommendations and their likely impact, on both individual members of the current House of Commons and their parties. The Conservatives are likely to gain significantly over Labour as a result of the changes, but there is much debate over the electoral data that the Commissions have to use, as laid down in the rules approved by parliament in 2011.
The Boundary Commissions for England, Northern Ireland and Wales have now published their initial recommendations for new parliamentary constituency boundaries. These are implementing the revised rules for such exercises introduced in the Parliamentary Voting System and Constituencies Act 2011. An earlier exercise deploying those rules began in 2011 but was ended prematurely by parliament in 2013. That decision delayed the procedure by five years; the Commissions now have to deliver a final set of proposals for new constituencies by October 2018, which it is anticipated parliament will approve for use at the expected next general election in 2020.
Those new rules introduced two major changes to the United Kingdom’s electoral cartography, each with a potential substantial impact on the composition of the next House of Commons. First, the number of MPs is to be reduced from 650 to 600: England will have 501 compared to its current 533; Scotland’s contingent will be reduced from 59 to 53 and Northern Ireland’s from 18 to 17; Wales will experience the greatest reduction, from 40 to 29 MPs. The second change is that with four exceptions (two for Scotland – Orkney & Shetland and the Western Isles – and two for England – for the Isle of Wight) all constituencies must have electorates deviating by no more than five percentage points from a UK average of 74,769; all must therefore have electorates between 71,031 and 78,508.
The combination of those two changes accounts for the bigger cuts in Wales than elsewhere. Currently Wales has 40 constituencies with an average electorate of 54,546, compared to an average of 70,234 for England (excluding the Isle of Wight) and 67,416 in Scotland. Only one of the current 40 Welsh constituencies has an electorate within the specified range, and so the current map has to be completely replaced.
The Scottish Boundary Commission will not announce its provisional recommendations until mid-October, at the request of the political parties there.

