Don’t misread the by-election results, the door is still open for Tories to squeeze back into No 10

Overinterpretation is the curse of the political classes. The prime example this week was the reading of Thursday’s by-elections as spelling doom for net zero – the target of a carbon-neutral economy by the middle of the century.

This is a problem mainly for Labour – according to many Labour MPs – because green policies are almost their only distinctive offering at the next election.

This interpretation is not wrong, but it requires several steps of reasoning that need to be tested. The first thing to be said about the by-elections is that Labour’s win in Selby and Ainsty was an outstanding result, comparable with the swings achieved in by-elections by Tony Blair as leader of the opposition.

It is not overinterpreting to say that the Selby result suggests that Keir Starmer next year could achieve the kind of swing Blair achieved in 1997. It may be that this prospect owes more, this time, to the Conservatives’ self-destruction than to Labour’s positive programme, but the numbers are comparable.

It is a matter of simple maths to point out that Starmer was too pessimistic about what this means when he received the Master’s blessing at the Blairfest on Tuesday. Starmer said that if he shifted votes from the previous election on the same scale as Blair did, he would end up with a majority of one in the House of Commons.

Apart from the formal majority having to be an even number, his projection is out of date. The collapse of the Scottish National Party means that Labour can hope to gain around 20 seats in Scotland. The Electoral Calculus model suggests that a swing comparable to that in 1997 would currently produce a majority for Labour of around 60, depending on the level of tactical voting.

So the first lesson of the by-elections is that Labour is well placed for the general election. Why the long faces on the Labour side, then, and why the corresponding chipperness among the prime minister’s team?

Uxbridge. The very word has come to mean “high expectations disappointed” in Labour circles, a word missed by Douglas Adams and John Lloyd in The Meaning of Liff (it should be between Uttoxeter, “a small but immensely complex device which is essentially the ‘brain’ of a modern coffee-vending machine”, and Valletta, “an ornate head-dress worn by a person in the belief that it renders them invisibly native and not like a tourist at all”).

Labour failed to win it in a by-election in 1972. New Labour failed to win it in a by-election two months after the Blair landslide in 1997: Blair was persuaded that it was winnable and broke with the convention that prime ministers did not campaign in by-elections, and John Randall still won it with a swing to the Tories.

Now Labour has failed to win it again, in equally promising circumstances. “It is a sticky blue constituency,” one Labour official told me. As the whole of outer London gradually becomes more and more Labour, the borough of Hillingdon holds out like a Tory Gaulish village.

The reason for Labour’s failure is the plan to expand the Ultra Low Emissions Zone (Ulez) to the constituency next month. This is nothing to do with net zero, because it is about air quality, not climate change. Indeed, it is nothing to do with nine out of 10 motorists in Uxbridge, whose cars are new enough to meet the emissions standard and avoid the £12.50 daily charge.

But this was not well understood. I am not sure I believe the Labour canvasser who said that “even people with Teslas in their front gardens thought it applied to them”, but it would seem that lots more people thought they would have to pay it than would actually be liable.

Nor is Ulez a particularly Labour policy. Sadiq Khan, the mayor of London, decided the extension, but it was Boris Johnson, his predecessor and the previous MP for Uxbridge, who started the policy in central London. And it was the Conservative government that made pandemic funding for Transport for London conditional on “proposals to widen the scope and level of these charges” three years ago.

None of that matters. It was seen as a Labour plan; people thought that they would have to pay; and they thought that by voting Tory they could stop it. As Starmer told Labour’s National Policy Forum today: “We are doing something very wrong if policies put forward by the Labour Party end up on each and every Tory leaflet.”

The message of Uxbridge is that Labour is vulnerable if voters think they might be hit financially. That is a message that reaches beyond those parts of London outside the North and South Circular, and it reaches beyond green policies – although those may be the most visible. Rachel Reeves, the shadow chancellor, has ditched the party’s Green Prosperity Plan for the early years of a Labour government but remains committed to borrowing an extra £28bn a year in the second half of the next parliament.

Climate change is a difficult subject for Rishi Sunak, because there are voices in his own party urging him to ditch net zero. If he yields too much to them, he could be portrayed as the prisoner of anti-science cranks. So we should expect more of him trying to label Labour as “eco zealots”, as he did last month, and presenting the Tories as the party of green pragmatism, always sensitive to the costs borne by the voters.

But the deeper message of Uxbridge is that Labour has to reinforce its defences against taxing and spending. The message of Starmer’s speech today was that if the party found it painful enough in the past two weeks, refusing to lift the two-child limit on welfare benefits, there is worse to come.

Tories will quote Starmer saying to Laura Kuenssberg last weekend: “A Labour government will always want to invest in its public services.” They will claim that what he means is that taxes will always be higher under a Labour government than under a Tory one. The problem for Starmer is that it is true. Many voters will even accept it as a price worth paying for better public services. But many others will not. Sunak will quote John Major: “Dogs bark, cats meow and the Labour Party puts up taxes.”

Labour’s hopes for the next election could be Uxbridged – “brought down to earth if the voters fear that the cost of a Labour government will be too high”.