In all my years reporting on opinion polls, I’ve never seen anything like this

The polls currently point to a bigger Labour landslide than in 1997, writes John Rentoul

This time the movement in opinion has been sharp, over a few days, with the average Tory line on the graph moving almost vertically down and the Labour line a mirror image upwards (Getty)

Most of the time, the trouble with opinion polls is that people’s views don’t change that much, or that quickly. I often try to explain that what might look like a big shift in voting intention, for example, is probably random statistical variation and not the response to a news story that obsessed journalists but which most voters didn’t notice at all.

Not this time. Before what I insist on calling the emergency Budget on 23 September (it was certainly an emergency afterwards, if not before), the opinion polls were so-so. Liz Truss, who had been prime minister for 17 days, had failed to enjoy the traditional popularity bounce that greets a new leader, but the nation had been distracted for most of that time by the Queen’s death.

Labour enjoyed the same sort of leads it had held since Boris Johnson announced his resignation, wavering around 10 percentage points. As is often the case, though, it takes a few days for the effects even of momentous events to filter through into opinion polls. The first couple of polls carried out wholly after Kwasi Kwarteng’s statement showed Labour leads of 13 and 18 points, but it wasn’t clear until 5.30pm on Thursday that something historic had happened.