Should any @UKLabour supporters be feeling decidedly chipper this morning, here's @PeterKellner1 providing a wee bit of rain on your parade by contrasting by-election with next-election results. History doesn't necessarily repeat, mind! https://t.co/qej0bBYQ7O pic.twitter.com/0yefEyZVmp

— Tim Bale (@ProfTimBale) December 2, 2022

On a brighter note for some of you: John Curtice: Labour is closer to a general election victory than ever, but it’s not in the bag https://t.co/vpg3xDTw4w https://t.co/qriKOI83tI

— Tim Bale (@ProfTimBale) December 2, 2022

After the result in Chester Peter Kellner published a piece which said

In all fifteen “big swing” by-elections between 1958 and 2012, the difference between the implied national lead and what actually happened was at least 12 percentage points, and after  all but three of the by-elections the drop was more than twenty points.

For example, ten years ago, Labour gained Corby on a similar swing to this year’s two comparable by-elections, Wakefield and Chester. But in Corby, Labour’s baseline was a national deficit of 7.2% – the amount by which the Tories defeated Labour in 2010. Taking that into account, the Corby result translated into an implied national lead for Labour of 18.2%.

By that measure, Labour fell short of its Corby performance last night. This time, the baseline was a nationwide Labour deficit of 11.8% at the last general election. This meant that a 13.8% swing in Chester translated into an implied national lead od 15.8%. And here’s the thing: after Corby, Labour went on to lose the following election. If Labour’s post-Corby history were to repeat itself precisely, then the Tories would win the next general election with a comfortable, and only slightly reduced, majority.

In other words, for Labour to secure a majority at the next election it must massively outperform its past record of translating mid-term by-election victories into its support at the following election.

Can Labour do that? Possibly. History does not always repeat itself. Each year sees a new edition of the Guinness Book of Records precisely because new records keep on being set. However, if I were a Labour strategist I would be more nervous today in private than the party claims to be in public – and if I were a leading Tory I would not be quite as downcast as the headlines suggest I should be

My own hunch is that the you should focus on by election seats where the government is the incumbent party, seats like Wakefield, North Shropshire, Tiverton & Honiton et al, where the results imply the government is on course for a shellacking.

But those who think the next election is doomed for the Tories and nailed on for a Labour majority there’s something in Kellner’s analysis to make you doubt your assumptions but as I said last week, I feel more comfortable laying a Tory majority than backing a Labour majority, to quote a recent Prime Minister, nothing has changed.

TSE