Pollster Profile
Ipsos UK: Monthly Voting Intention Poll & Methodology
Ipsos — formerly known as Ipsos MORI — is one of the oldest and most established polling organisations in the United Kingdom. The company has been tracking British public opinion since the 1970s, giving it one of the longest continuous time-series of political data of any UK pollster. That depth of historical data is one of Ipsos’s most distinctive assets: trends visible over decades provide context that no firm founded after 2010 can offer.
In 2022, Ipsos MORI rebranded to simply “Ipsos,” in line with a global rebrand of the wider Ipsos group. The MORI half of the name came from the Market & Opinion Research International brand, which Ipsos acquired in 2005. The combined entity brought together two of the UK’s most respected research traditions, and the Ipsos Political Monitor — the flagship monthly voting intention product — continues that heritage.
Ipsos methodology
The Ipsos Political Monitor is published monthly and uses a mixed-mode methodology that distinguishes it from most other UK pollsters:
- KnowledgePanel (online, probability-based): The majority of the monthly sample is collected online via Ipsos KnowledgePanel — a probability-based online panel where respondents are recruited via random address sampling rather than self-selection. This is a methodologically stronger basis for representativeness than opt-in panels, because it means the panel is not populated exclusively by people who actively sought out an online survey opportunity.
- Face-to-face (selected waves): For some surveys, Ipsos continues to use face-to-face interviewing — one of very few UK pollsters still to do so. Face-to-face fieldwork is more expensive but reaches demographic groups that are under-represented in online panels, particularly older respondents without reliable internet access and those in less digitally engaged socioeconomic groups.
- Sample size: Typically 1,000 to 1,200 GB adults per monthly poll. This is at the lower end of the UK market for a voting intention tracker, but the probability-based sampling approach compensates for the smaller raw size.
- Weighting: Age, gender, region, working status, and past vote recall. Ipsos applies interlocking age-gender weights rather than marginal weights, which more accurately reflects the joint distribution of age and gender in the population.
- Don’t know handling: Ipsos publishes figures both including and excluding those who say they do not know which party they would vote for. The headline figure typically excludes don’t knows, but the full tables allow analysts to see the distribution including them.
Ipsos voting intention figures (May 2026)
Source: Ipsos Political Monitor, May 2026. Figures rounded to nearest percent. GB adults.
Ipsos accuracy record at UK general elections
Ipsos MORI’s (now Ipsos’s) accuracy record at UK general elections spans more than 40 years. Their record is mixed — as it is for all UK pollsters — but their performance at recent elections has been broadly solid.
| Election | Ipsos final poll | Actual result | Assessment |
|---|---|---|---|
| 2024 | Lab 36%, Con 22%, Ref 16%, LD 13% | Lab 34%, Con 24%, Ref 14%, LD 12% | Broadly accurate; Con slightly underestimated |
| 2019 | Con 44%, Lab 33% | Con 44%, Lab 33% | Near-perfect on top two parties |
| 2017 | Con 44%, Lab 36% | Con 42%, Lab 40% | Overstated Con lead; missed surge |
| 2015 | Con 36%, Lab 35% | Con 37%, Lab 31% | Industry-wide failure to call Con majority |
What makes Ipsos different from other pollsters?
Several features of Ipsos’s methodology set them apart from the higher-frequency online pollsters:
- Probability-based sampling: Ipsos KnowledgePanel’s address-based random sampling provides a stronger theoretical basis for representativeness than opt-in panels. People who would never voluntarily join an online survey panel are included because they are recruited directly by post.
- Long time series: Monthly tracking since the 1970s enables long-run trend analysis that no other UK pollster can provide. The ability to compare 2026 figures directly with 1985 or 1997 figures on identical question wordings is genuinely valuable for historical context.
- Issues and leadership tracking: Beyond voting intention, Ipsos publishes monthly data on best party on key issues (economy, NHS, immigration, etc.), net satisfaction with the Prime Minister, and trust in party leaders. This issues data provides crucial context for understanding why VI figures are moving.
- Interlocking weights: The use of interlocking rather than marginal demographic weights produces a more accurately calibrated final sample.
Ipsos house effects
Compared to online-only pollsters such as Techne or Redfield & Wilton, Ipsos tends to record somewhat lower figures for Reform UK and somewhat higher figures for the Conservative Party. This is consistent with Ipsos’s probability-based panel reaching different demographic groups than opt-in online panels.
Ipsos figures for Labour tend to sit close to the cross-firm average — neither systematically higher nor lower than other major firms. Their Lib Dem figures have historically been accurate at elections, which is notable given that the Lib Dems are a notoriously difficult party to poll correctly (their support tends to be geographically concentrated in ways that distort national VI figures).
The Ipsos Political Monitor: beyond voting intention
The monthly Political Monitor covers more than just voting intention. Regular tracks include:
- Net satisfaction with the Prime Minister: A long-running series comparing Keir Starmer’s approval against previous Prime Ministers at the same point in their tenure.
- Best party on key issues: Which party voters trust most on the economy, NHS, immigration, and defence. These issue ratings often diverge significantly from voting intention, revealing structural weaknesses and strengths that VI figures alone cannot show.
- Most important issues: An open-ended question asking what respondents consider the most important issues facing Britain. The aggregate response is one of the most useful measures of the public’s political agenda — and often differs markedly from the media’s coverage priorities.
- Optimism/pessimism: A long-running economic optimism tracker that predates many of the current polling firms entirely.
How UKPollingData uses Ipsos data
UKPollingData.com includes all monthly Ipsos Political Monitor voting intention figures in our national polling average. Ipsos figures receive full weight without house-effect correction, reflecting their track record of accuracy and the methodological robustness of their probability-based sampling approach.
Compare Ipsos against all other firms in the voting intention tracker. For the full explanation of how we weight different pollsters, see the methodology page. For leader approval data drawn from Ipsos monthly surveys, see leader approval ratings.