How Britain draws its electoral boundaries

By F.H.

BRITAIN’S parliament houses 650 MPs, each of whom represents a constituency. But the number of voters in each constituency varies wildly. Often this is due to geographical quirks: the smallest constituency is the Outer Hebrides, a chain of islands off Scotland’s north-west coast with around 21,200 voters; the biggest (109,900 voters) is the Isle of Wight. Demographic shifts also contribute to discrepancies. Over the past 70 years or so, Britain’s population has drifted from north to south and from cities to suburbs, swelling the size of some electorates and shrinking others. Every so often electoral boundaries are redrawn to correct these irregularities. How?

On September 10th the government announced plans to change Britain’s electoral map. These would cut the number of MPs to 600 and create constituencies with around 75,000 voters each, though exceptions have been made for islands. This idea was first touted by David Cameron in 2009 as a way of cutting the cost of politics. It is also meant to correct a bias in Britain’s electoral system. The Labour Party often does well in areas such as Wales (where constituencies have 56,000 voters on average, 16,000 fewer than those in England) in which fewer votes are needed to elect an MP. Tories complain that this allows Labour to win parliamentary majorities with a smaller overall share of the popular vote. But if constituency sizes are evened out, other quirks of Britain’s first-past-the-post system (notably the performance of smaller parties and the importance of closely contested marginal seats) will give different grounds for complaint.

The proposals were drawn up by four separate commissions, one each for England, Scotland, Wales and Northern Ireland. In America, state legislatures are usually responsible for drawing the boundaries of electoral districts. This often leads to arrangements that favour the locally dominant party. In Britain, although parliament can choose the total number of MPs and must vote for the changes to become law, politicians have no say in how the boundaries are set. Instead, the commissions are headed by a senior judge, supported by a mixture of lawyers and civil servants. They take into consideration current boundaries, population changes and natural obstacles, such as lakes or mountains, that might make it tricky for an MP to move around and tend to constituents. The process also involves lengthy public consultations. After receiving some 25,000 responses, the English commission amended more than half of its original recommendations.

Still, not everyone is happy. Under the proposals, Wales would lose more than a quarter of its MPs, compared with a reduction of just 6% in England. Labour, which stands to lose the most, has blasted the new boundaries as a “power grab” and says the figure of 600 MPs was “plucked out of thin air”. They argue that the changes will mean fewer MPs to scrutinise the government. The plans have also rekindled nationalist fervour in Cornwall, in south-west England. Impassioned Cornish pleas, including one sung entirely in Cornish, could not stop the English commission from recommending a constituency that merges Cornwall with parts of neighbouring Devon. The weightiest opposition could come from senior Tories worried about seeing their seats swallowed up. They are likely to enjoy a stay of execution. With Brexit talks in the crunch, Theresa May is unlikely to trouble her fractured party by forcing the proposed boundary changes through parliament anytime soon.