For the third time in just over a decade, a new map of parliamentary constituencies is being designed. This one will likely be implemented. Charles Pattie and David Rossiter argue that, despite the misconceptions of both Labour and the Conservatives, the review is neither a ‘gerrymander’ against one, nor redressing an imbalance that harmed the other. But these entrenched views could yet threaten the future of First Past the Post as the system for Westminster elections.

Here we go again. For the third time since 2010, a new map of Westminster parliamentary constituencies is being designed. The Boundary Commission for England released its preliminary proposals on 8 June (the Commissions for Scotland, Wales and Northern Ireland will follow suit in the coming months). Final recommendations will appear in the summer of 2023. This time (the previous two attempts at redistricting faltered before being implemented) the new map is very likely to be adopted. And if past reviews are any guide, the process will be carried out amidst claims and counterclaims regarding potential winners and losers, and whether there is deliberate bias in the process.

Of course, redrawing the constituency map inevitably involves winners and losers, even when (as in the UK) done by politically impartial Commissioners. Previous reviews have tended to result in relative losses of seats for Labour and gains for the Conservatives (smaller parties tend to suffer greater disadvantages from the disproportional nature of First Past the Post (FPTP) than from the effects of boundary reviews). Some Labour figures are likely to argue (as they have done in the past) that the review is a gerrymander against their party, and so drives a nail into the coffin of its electoral chances. On the other side some Conservatives will argue the review simply redresses substantial anti-Conservative bias in the old seats – a nail in the coffin in which that bias is to be buried.

Both views are wrong, but for different reasons.