The Lib Dem win in Chesham and Amersham is bad news for the Tories, but even worse for Labour

This result vividly repeats the message that, while the Leave vote is united and has coalesced in the Conservative Party behind Boris Johnson, the Remain vote is divided

It is bad news for the Conservatives, but it could be even worse for Labour. The Liberal Democrat by-election victory in Chesham and Amersham reflects the realignment of British politics, as the Conservatives gain support in northern working-class Leave areas – which means they are vulnerable in southern middle-class Remainland. But while it is Labour that loses out in places such as Hartlepool, the main opposition party doesn’t gain in places such as Chesham and Amersham.

This Lib Dem victory looks remarkably like the familiar politics of yesteryear, when the pre-coalition Lib Dems and before them the Liberals would score stunning by-election upsets by harvesting protest votes, mostly against Conservative governments but also against Labour ones. What it does confirm is that the party still has a formidable organisation on the ground.

But this win had some new elements of post-Brexit politics. It was a protest vote all right, but it wasn’t expressing a sense of national dissatisfaction with the government or the prime minister, who remain moderately popular. The Lib Dems ruthlessly exploited the one local issue – opposition to HS2, the rail line running through the constituency, even though the party nationally supports it.

What Sarah Green, the new Lib Dem MP, seems to have done best, though, is to capture the sense that the Brexit Conservative party has moved away from Remain-voting graduate professionals in the London commuter belt. Those voters have taken the electoral system into their own hands, seeing a chance to unite tactically against the Tory, which meant Labour suffered a classic by-election squeeze – a squeeze that was so efficient it reduced the party’s share of the vote to 1.6 per cent.

This was even more remarkable than the 3.7 per cent share Labour recorded in the Richmond Park by-election, a Lib Dem gain in the immediate aftermath of the EU referendum, where the local Labour Party claimed more members than voters.

Of course, Lib Dem gains have come and gone before. The last seat the Conservatives lost in a by-election, Brecon and Radnorshire in August 2019, was held by Jane Dodds, the Lib Dem, for just four months before the Tories retook it in the general election. But this one could be different.

Chesham and Amersham was a safe Tory seat – it was not on the target list of Remain-voting seats in the south-east where the Lib Dems are in second place that could be vulnerable to a reverse “red wall” effect. Dominic Raab in Esher and John Redwood in Wokingham were the kind of prizes Jo Swinson thought she could claim last time, but Chesham and Amersham is similar – it is just that it has always been more Tory.

Labour might hope to benefit from the mirror image of the collapse of its red wall too. It has been able to pick up southern middle-class seats such as Canterbury and (briefly) Kensington. But last night’s Lib Dem triumph is going to make Keir Starmer’s pitch to those kinds of seats more difficult.

The Chesham and Amersham result vividly repeated the message that, while the Leave vote is united and has coalesced in the Conservative Party behind Boris Johnson, the Remain vote is divided. Remain voters show that they can use the voting system to unite behind the best Remain candidate when it counts. Even the Green vote was squeezed in the by-election, although Carolyne Culver, the Green candidate, won twice as many votes as Natasa Pantelic for Labour.

But that kind of tactical voting is harder to organise in a general election – especially one that will be fought on new parliamentary boundaries, as the next election is likely to be. That means the non-Tory vote is likely to be hopelessly split.

The unity of the Leave vote is going to be underlined in the next by-election, in Batley and Spen, in West Yorkshire, where Labour may not lose as badly as it did in Hartlepool, but it would be a miracle if Kim Leadbeater holds on to the seat.

Starmer can only watch gloomily while the calls for the party to back proportional representation and a pact with other non-Tory parties will grow at his annual conference in Brighton in September. But if the Lib Dems can win seats such as Chesham and Amersham, why would they need to alienate soft Tory voters by doing deals with Labour?