Can Anyone Actually Win Gorton and Denton? The Data Behind Britain's Most Unpredictable By-Election

Can Anyone Actually Win Gorton and Denton? The Data Behind Britain's Most Unpredictable By-Election - Analysis

The Gorton and Denton by-election is proving difficult to predict - The Swingometer and Ben Walker have already written excellent analysis on the race. Why are by-elections, and particularly this one, so difficult for pollsters and predictions? Subscribe now What goes into a by-election? I looked at the last 22 by-elections and the baseline swings and factors that go into who wins and loses. Note that these should be viewed as trends - there aren’t enough recent by-elections to be statistically significant - also note this was during the collapse of the Conservative party, however Labour now find themselves with similarly low approval ratings. Governments lose 86% of their by-elections (12 of 14 since May 2021) As we can see, being the incumbent government already carries a heavy penalty. I then looked at the swings depending on the reason for the by-election: Notably, Uxbridge had a smaller swing and was retained by the Conservatives on a much reduced majority, after the campaign was fought on the local matter of ULEZ. These figures also exclude the Southend West by-election following the murder of David Amess, as the race was uncontested. For an example of a non scandal by-election, we can look at 2021 Old Bexley and Sidcup. This by-election was called due to the death of the incumbent, and resulted in a 10pp swing, with the Conservative Government at the time retaining the seat. In Gorton and Denton, Andrew Gwynne was suspended from Labour in February 2025, after writing offensive WhatsApp messages. He then resigned in January 2026, citing health reasons. Modern governing parties typically underperform their previous general election vote by 10-25pp in by-elections, creating a hurdle from the start. The Turnout and Demographics Question By-elections have much lower turnout than General Election - usually 35-45% vs 60-70%.

This analysis examines UK political polling trends, seat projections, and election dynamics. PollCheck provides comprehensive coverage of Westminster elections, Scottish Parliament elections, and Welsh Senedd elections, tracking polling data from major UK pollsters including YouGov, Find Out Now, Opinium, More in Common, and others.

Our analysis uses uniform national swing (UNS) methodology to project seat outcomes based on current polling data. We provide free tools including seat calculators, interactive maps, and detailed polling trend visualizations to help understand UK political dynamics.