Revolt on the left: getting to know Labour's 'progressive defectors'

This research first appeared on the New Statesman. It was conducted with 38 Degrees and Convergent Opinion.

The full report can be downloaded above or you can just see the graphs from the report with minimal commentary by clicking 'just give me the graphs'.

What we wanted to find out

• Who are Labour’s ‘progressive defectors’, demographically, geographically and attitudinally? In what seats do they matter most
• Why are they switching and how does it compare to other voter groups?
• How likely are tactical voting imperatives to influence them?
• What kind of offer, if anything, might bring them back to Labour or attract them to a party generally? Can they be united with more right-leaning swing voters?

We define progressive defectors as anyone who voted Labour in 2024 but has switched to one of the Greens, Plaid, SNP or Liberal Democrats.

What we did

• A core survey, including a special sample boost of 2024 Labour voters. This was commissioned via NorStat in December 2025/January 2026.
• MRP analysis of different groups within the electorate, including isolating left and left curious Labour voters in each constituency (see table below).
• A multi-factorial Randomised Control Trial (RCT) experiment, known as a ‘vignette experiment’, to isolate and analyse different factors shaping voting intention.

In total we spoke to over 9,000 UK voters.

What we found

• Progressive defectors matter in electoral battleground constituencies across the country, especially Wales and the ‘Blue Wall’ commuter belt seats that played an important part in Labour’s 2024 election victory.
• Left defectors are not a ‘PMC Lanyard class’, but mostly frustrated lower middle class graduates.
• Their disaffection is slightly more values based than competence based, even if they also feel the same impatience for change as the public at large.
• These voters are open to returning to Labour and have a reasonable-minded posture to government - but it shouldn’t be assumed they will do so automatically via tactical voting. They are genuine swing voters and should be thought of as such.
• The best working theory of tying these sorts of voters into the same coalition as 'swing right' voters centers on affordability populism - picking fights on the subject of the cost of living and driving attention to that agenda. Outside of that, some issues continue to work disproportionately well with progressive defectors - such as closer ties with the EU, confident signalling on climate change and progress on child poverty

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