Corbyn’s Labour has done well. To win power it needs to do far better | Martin Kettle

At a memorial event yesterday for the political scientist Anthony King, John Bercow recalled one of the things that always made King such an illuminating commentator on British elections. The House of Commons Speaker – a student of King’s at Essex University – observed that, while party politicians reflexively respond to election results with exaggerated claims and pitiful denials, King had a simple motto that cut through the spin: “Focus on the evidence.”

Tony King would have loved the 2017 general election. His absence from it is one of the lesser reasons why he is so much missed. King would certainly have been withering about Theresa May’s multiple misjudgments of the past few months. She is indeed fortunate that Tony did not live to write about her in his uncompleted book on Britain’s postwar prime ministers.

But he would surely have cast a critical eye over some of Labour’s responses to the 8 June results too. Focusing on the evidence, he would rightly have been impressed at Labour’s nearly 13 million votes, its 40% vote share, its 30 more seats, and the way Jeremy Corbyn confounded the experts with his campaign and style. Yet he would, I suspect, be cautious about claims that a Labour government is today just “one more heave” away.

That is not to say that Corbyn has no hope of being prime minister in a few months’ time. He plainly has such a chance. If there is another snap election – a possibility, though not an easy one to bring about – Labour is extremely well placed to oust the Conservatives at the polls. There is even the (more remote) possibility that, as happened under Ramsay MacDonald back in 1924, events could evolve in such a way that a minority Labour government replaces the current Tory minority administration.

But the evidence of 8 June contains warnings for Labour, as well as the many encouragements. The most obvious is simply that Labour did not win the 2017 election; it lost. Labour’s seat total of 262 today is merely back to about what it was – 258 – when Gordon Brown lost power in 2010. Labour remains 64 seats short of an overall majority. And 18 of Labour’s most statistically winnable seats are in Scotland, where the SNP remains a formidable rival.

Labour recorded a 2% swing from the Tories on 8 June. But the Tory vote increased too. For Labour to win 64 more seats from them requires a further swing of 6%. To capture its 64th most winnable seat from the Conservatives next time means defeating Graham Brady, who chairs the Conservative 1922 committee, in Altrincham and Sale West – a seat that Brady won in the Labour landslide of 1997, and in every contest since.

All these things are, in principle, possible. But it has to be faced that they are also difficult. It is not enough to say that what worked in June 2017 will work again. That is why it is so important for Labour to be open-minded rather than dogmatic about addressing the next phase. Labour should face the truth that it had a lot of luck in 2017, as well as its hard-won successes. Some of that luck was made by Corbyn. A lot of it, however, was gifted unintentionally by May, not least in her failure to challenge the Labour manifesto on the economy. But it has to be possible for Corbyn enthusiasts and Corbyn sceptics to talk to each other respectfully, on the basis of evidence. Both sides have things to learn.

So it ought not to be considered a thought crime, as it has sometimes felt to be in the past two weeks in certain circles and with certain critics, to say that Labour still has a very steep slope to climb. To argue that Labour still needs to win votes, seats and arguments in the centre ground of British politics, among voters who consider themselves as moderates must not be treated as a sign of disloyalty. The 2017 election result doesn’t prove to me that voters are yearning for a leftwing programme. It suggests that they turned against Theresa May. When asked, three-quarters of the population still consider themselves centrists, or on the centre-left or centre-right.

In a presentation on the election for the Policy Network organisation this week, the former YouGov chief Peter Kellner pointed up some of the issues. Mid-20th-century social class loyalties no longer apply. On 8 June Labour’s voters instead comprised a coalition of groups rather than traditional blocs. Regional differences were very marked. As a result, Kellner argued, Labour may be moving away from being a “whole nation” party towards being a “coalition of interests” party.

If that’s right, which of course it may not be, then it makes sense to examine whether such a coalition can hold together, and whether it provides electoral rock or sand for building the new support Labour requires to win. For it can be argued that each of the coalition groups defines Labour in ways that make centrist-inclined voters harder to capture.

Labour’s coalition is particularly strong among what have been called the exam-passing classes (students, voters with degrees), the young, public sector workers (white collar as well as blue), voters who rely on in-work benefits, and some minority-ethnic groups. Yet young voters are a declining part of an ageing society, public sector workers are a declining part of the workforce, and minority-ethnic voting patterns are less settled now than in the past.

Political allegiances are also more volatile. Look at the dramatic rise and fall of Ukip support in the 2010s. Look at the changes in Scotland between 2011 and 2017. The 2017 election was also one of the most volatile for decades. Manifestos and the campaign itself both mattered more than in the past. The electorate’s views before the Tory manifesto launch on 19 May were quite different from their views afterwards.

A further factor, according to the strategist Deborah Mattinson, is that after 19 May many voters decided to support Labour in spite of Corbyn, not because of Corbyn. None of this means that the move to Labour won’t last, or that Corbyn did not have a good campaign from which he has emerged as a more credible leader. Equally, though, it could mean that the Labour surge is contingent, and may dissolve again.

These are fascinating political times. But they are also very uncertain times. In France, a radical centrist experiment contrasts with Britain’s apparently deep post-referendum division. Those who affect certainty about everything are false prophets. In such circumstances, it makes better sense than ever to focus on the evidence.