The next election just got (even) harder for Keir Starmer – because of new constituency boundaries

The new constituency boundaries mean Labour will start from an even lower base than the record low number of seats it won last year, says John Rentoul

Labour already needed the biggest swing in votes since the war – bigger even than the 10 per cent swing recorded by Tony Blair in 1997 – to win a majority in the House of Commons at the next election. That meant the Labour share of the vote had to go up by more than 10 percentage points from the 33 per cent the party won last year, and the Conservative share had to go down by the same amount. 

That was before yesterday. At 1.07pm on Monday, the Parliamentary Constituencies Act 2020 received the royal assent and became law. At a stroke, the next election became even harder for Keir Starmer to win. 

This is not a wicked Tory plot to gerrymander seats in their favour. In fact, the Tory party has fought the last few elections at a disadvantage, because out-of-date boundaries mean that their seats tend to have larger electorates than Labour ones.

For a decade the government has been unable to do anything about it, because of David Cameron’s populist promise in 2010 to reduce the number of MPs from 650 to 600 to “cut the cost of politics”. In the end, it proved impossible to persuade MPs to abolish their own seats, even when the government had a majority. 

Boris Johnson wisely dropped the promise to shrink the Commons, and with a majority of 80 was able to get a bill through to instruct the four independent boundary commissions – one each for England, Scotland, Wales and Northern Ireland – to begin their work. Significantly, the new law provides for the new boundaries, when they are drawn up by July 2023, to come into effect automatically, without a further vote in parliament. 

We don’t know exactly what effect the new boundaries will have, because the commissions have to start again from scratch (the last review produced all sorts of interesting changes that never came into effect, such as abolishing Jeremy Corbyn’s seat of Islington North). But we know that the overall effect will be to increase the number of seats in the south of England and reduce them in the north, the midlands, and in Wales. And that means Labour will start from an even lower base than the record low number of seats it won last year. 

The Electoral Calculus website calculated what would have happened at the last election if the 2018 review had been enacted. Instead of a majority of 80 in a Commons of 650 MPs, Johnson would have won a majority of 104 in a chamber of 600. That is the sort of effect that the forthcoming review could have: in effect transferring about 16 seats from Labour to Conservative before a single vote has been cast. 

This assumes, of course, that the next election takes place after July 2023, when the new boundaries come into effect (after the Fixed-term Parliament Act is abolished, the latest possible date for the next election will be 28 January 2025). 

The effect of the new boundaries depends partly on how effectively the political parties are able to lobby the independent commissions when they hold their public consultations, although the commissions’ flexibility has been reduced by the requirement that constituency electorates may not vary by more than 10 per cent (5 per cent above or below a target size) – except for the five island constituencies (Anglesey; two on the Isle of Wight; Orkney and Shetland; and the Western Isles). 

And it may be that the pro-Labour bias of the current boundaries has been diluted by the Tories’ inroads into traditional Labour territory in the north, midlands and Wales – the very places that have been losing population in recent decades. But this is only a matter of softening the blow; the hard fact remains that the scale of Labour’s challenge will be greater than it was last time. 

Labour has already lost Scotland, which used to provide a block of 40 or so seats on which it could rely; at the next election it is likely in effect to lose another 16. Of course it is possible to overcome such obstacles; after all, Tony Blair with his majority of 179 could have taken such losses in his stride. But that means Starmer has to win something like the second biggest postwar swing (equivalent to Margaret Thatcher’s 5 per cent in 1979 or David Cameron’s in 2010) just to hope to be prime minister of a minority government in a hung parliament.