New parliamentary boundaries suggest Boris Johnson could call an election in just two years’ time

The most important question about the new constituency boundaries is how much the Conservatives will gain from them, but we won’t have a very accurate estimate of that effect for some time. The maps published today are the initial proposals for England. Plans for Scotland, Wales and Northern Ireland will follow. The independent commissions will listen to objections and then publish revised plans, on which there will be further consultations before the final boundaries come into effect in July 2023.

However, we know that the changes will benefit the Conservatives, because Tory seats have tended to grow in population, while Labour ones have shrunk. The purpose of the boundary review is to equalise electorates between constituencies, which means more seats in generally Tory areas and fewer in Labour.

The effect is unlikely to be as big as it would have been in the previous two attempts to redraw boundaries, which were abandoned because the government was trying not just to equalise seats but to reduce the total number of MPs. That created too many individual losers, including among Tory MPs, which made it impossible to get the changes through the Commons.

This time the government has left the total unchanged – and it has taken the extra precaution of not allowing parliament a further vote on the proposals. Now that parliament has passed the Parliamentary Constituencies Act 2020, the changes will come into effect automatically on 1 July 2023.

Since the previous attempts to update the electoral map, the Conservatives have made gains in traditional Labour seats, while Labour support has tilted in favour of the growing urban middle class, so the disparity in the average size of constituencies between the parties is not so great. Robert Hayward, the Conservative peer and elections guru, estimates that the new boundaries will be worth between five and 10 seats to his party. (As opposed to the equivalent of about 16 in the last review.)

On the face of it, it seems perverse to suggest that the current boundaries are biased in Labour’s favour. Projections suggest that if Labour had been as far ahead in share of the vote as the Tories were at the last election, Jeremy Corbyn would have had a majority of two when Boris Johnson had a majority of 80. But this is not the product of unequal constituencies; it is the result of the differing behaviour of Tory and Labour voters. Tory voters are more likely to turn out to vote in marginal seats, while Labour votes tend to pile up uselessly in their own safe seats and those of their opponents.

This is a remarkable reversal from the 1992-2010 period, when it was Tory supporters whose votes were wasted – in 1997 Tony Blair won by about the same margin of votes as Johnson, and was rewarded with a Commons majority twice as large. To make matters worse for Labour, it has now lost Scotland, which used to be an efficient secondary motor for turning Labour votes into parliamentary seats.

All of which is interesting, and if you want to know more about biases in the British electoral system I recommend an analysis by Tim Smith for the LSE, but it may be that the main significance of the boundary review will be as a clue to the timing of the next election.

There had been some speculation that the prime minister, once he has freed himself from the shackles of the Fixed-term Parliaments Act, which is due to be repealed in this parliamentary session, might call a snap election next year, before his vaccine-induced popularity wears off, or the year after, before the bills of the coronavirus emergency start to arrive, due in the form of higher taxes.

But the new boundaries give him an incentive to wait. A bonus of 5-10 seats is not the kind of gift that any prime minister is likely to treat lightly. So I think the earliest likely date of an election would be in July 2023, as soon as the new boundaries take effect.

Because the last election was held, unusually, in the middle of winter, which is not the ideal time, Johnson seems to have two main options: to go in the summer of 2023 or that of 2024. This would mean, instead of the four-year parliament that was the convention before the Fixed-term Parliaments Act, or the five-year term it prescribed, he has to go for either three-and-a-half years or four-and-a-half.

So that is my prediction: the next election will either be in July 2023 – in which case Boris Johnson will announce it on about this day in two years’ time – or in May, the conventional election month, 2024.