The “falling ladder” is now much less apparent. In fact, on this measure, the relationship between Labour voting and occupational characteristics was quite stable between 2010 and 2019, with a small decrease in the strength of association between 2017 and 2019. The relative stability of this overall relationship does not, however, imply the absence of significant changes in either Labour votes share or blue-collar population shares in individual parliamentary constituencies. Labour vote shares have increased substantially in many metropolitan areas with high proportions of university graduates, and have fallen substantially in some constituencies with high shares of blue-collar workers, low shares of graduates and older, whiter populations; this pattern has been widely noted and discussed.

But Labour’s vote share has also increased substantially in other areas with high blue-collar population shares, particularly in constituencies in cities such as Birmingham, Bradford, Liverpool and Manchester.

In contrast, the relationship between Conservative voting and occupational characteristics does change, becoming markedly weaker between 2010 and 2019. In turn, this means that the relationship between the Labour-Conservative margin and occupational characteristics became weaker between 2010 and 2019, but this tells us very little about working class support for Labour.

If Labour’s working-class support has not “collapsed” since 2010, what is the underlying story?

It cannot be reduced to a snappy one liner using these data, but the forthcoming British Election Study post-mortem will provide more concrete evidence. In the meantime, we can observe that overall Labour and Tory blue-collar voting patterns were essentially unchanged between 2010 and 2015, when the Liberal Democrats slumped and UKIP surged. Tory voting increased in blue-collar areas when it was UKIP’s turn to collapse in 2017, while Labour’s vote share increased across the occupational spectrum. Finally, in 2019 Labour’s vote share fell across the board. It seems likely that Labour lost blue-collar voters to the Tories and white-collar voters to the Liberal Democrats, but we will have to wait for survey data to be sure.

What, therefore, does the “falling ladder” plot demonstrate, if not a collapse in working-class support for Labour? One possibility is that information on employment characteristics from 2011 becomes an increasingly poor predictor of election results as time goes by. Another is that the relationship between blue-collar employment and political preference is very sensitive to the occupational definition used, and a third is simply that linear regression summary lines are very sensitive to outliers.

The relationship between occupational class and Conservative-Labour vote shares has been heavily studied, and subject to extensive debate since at least the 1970s. There is no doubt that the relationship between occupational characteristics and voting behaviour changed substantially over the course of the twentieth and twenty-first centuries – as has the structure of employment – and that the question of class has been central to Labour’s electoral strategies and fortunes since Gaitskell led the party.

It is not clear, however, that the relationship between occupational characteristics and Labour voting has changed dramatically since 2010. This observation should be borne in mind when considering the strategic conclusion of Cutts, Heath, Goodwin and Surridge, i.e.: