When did it start going wrong for Labour? The initial inspiration for this article was a tweet, which circulated widely after the party’s defeat in December, showing the fall in its majority in Bishop Auckland since 1997. From a high of 21,064 in 1997, it fell election on election, to end in defeat in 2019.

Or as Rebecca Long Bailey put it in an interview with Sophie Ridge: “We’ve also got to recognise that the decline of our support in these seats hasn’t happened overnight. It has been happening over a period of time, certainly over the last ten years”.

This sudden micro-level interest in constituencies’ electoral histories is part of an attempt — genuine in some cases, transparently not in others — to try