June Polling Averages: Is the two-party system back?

Has the death of two-party politics been greatly exaggerated?

June was a very eventful month in British politics. Andy Burnham won the most consequential UK parliamentary by-election for decades, in Makerfield, precipitating Keir Starmer’s announcement that he would step down as Prime Minister.

On the same day as the Makerfield by-election, the Conservatives won a by-election in Aberdeen South. This was the Tories first UK parliamentary by-election victory in Scotland since 1967.

These two by-election results triggered some commentary along the lines of ‘the death of two-party politics has been greatly exaggerated’, as the headline of Matthew Parris’s Spectator article put it.

Given that this blog series is charting what we see as the unprecedented fracturing and ‘breakdown’ of the British party system, it seems only right that we engage with the suggestion that two-party politics is not dead at all.

Firstly, it is worth looking at June’s polling averages, where there are some small signs of encouragement for the traditional two big parties of British politics. The combined Labour + Conservative vote share has crept above 40%, for the first time since July 2025. Labour’s score of 21% is their highest since August 2025, while separate YouGov leadership polling shows Kemi Badenoch’s favourability improving and also that she has a comfortable lead over Nigel Farage as ‘best PM’.

Meanwhile, Reform UK has recorded their joint lowest vote share (26.4%) since April 2025 and the Greens (12.3%) their lowest since December 2025.

June UK General Election Polling Averages

The average (mean) vote shares from the most recent June poll, by each of the nine polling companies who published a UK general election poll during June, is as follows:

Party / Polling average / Change*

Reform UK 26.4% -1.4
Labour 21.0% +1.1
Conservatives 19.1% +0.8
Greens 12.3% -1.3
Liberal Democrats 12.0% -0.1
Others 9.1% +0.8

* Compared with May’s average - Each month a different combination of pollsters will publish polls, so this change is not strictly comparing like with like, but gives a general sense of change

June’s polling average was compiled using data from the following pollsters – BMG; Deltapoll; Find Out Now; Good Growth Foundation; J.L. Partners; More In Common; Opinium; Survation; YouGov.

We will have to wait to see how polling data develops in the early weeks and months of an Andy Burnham premiership, which now looks all but inevitable. It is of course conceivable that Labour will continue to build on what has already been a small bounce in support since Starmer’s resignation announcement. It is also perfectly possible that Kemi Badenoch’s improved personal ratings will start to translate into improved vote intention polling for the Conservatives.

However, there would have to be very dramatic polling changes to go from the situation as it stands to one in which the return of two-party politics could be reasonably declared. It’s not only polling data either, just two months ago we saw the most fragmented set of English local election results on record, with five parties recording over 15% in the Projected National Share (PNS) of votes.

While obviously impossible to know for certain, there are a couple of underlying factors that indicate a return to two-party politics is unlikely.

Move away from two-party politics is a long-term phenomenon

Although the ultra-fragmentation of British politics that we have seen in the last couple of years is unprecedented, the trend away from two-party politics is actually a long-term phenomenon, decades in the making.

Over the course of the last 80 years, allowing for inevitable fluctuations, the combined Conservative and Labour vote share at UK general elections has been on a steady decline, from more than nine in ten votes during the 1950s, to fewer than six in ten votes at the 2024 UK general election.

Chunking up the elections into three blocks shows how the trend has progressed.

In the eight general elections between 1945 and 1970, the average (mean) combined Conservative and Labour vote share was 91.3%.

At the February 1974 general election, the combined Conservative and Labour vote share fell below 80% for the first time in the post-WWII era and at the eight general elections between Feb 1974 and 2001, the average (mean) combined Conservative and Labour vote share was 74.6%.

At the 2005 general election, the combined Conservative and Labour vote share fell below 70% for the first time in the post-WWII era and at the six general elections between 2005 and 2024 (when the combined Conservative and Labour vote share fell below 60% for the first time in the post-WWII era), the average (mean) combined Conservative and Labour vote share was 69.2%.

As they say in financial adverts, ‘past performance is not indicative of future results’, however this data clearly shows how the recent ultra-fragmentation of British politics is the continuation of a trend stretching back decades.

It also highlights how far the combined Labour and Conservative vote share would have to climb from its current polling position of 40.1%, just to reach the record post-WWII low of 57.4% recorded at the 2024 general election.

Two-Party Vote Share 1945-2024

https://public.flourish.studio/visualisation/29560561/

Multi-dimensional attitudinal divides driving multi-party politics

The long-running British Social Attitudes (BSA) survey has two batteries of questions that measure people’s positions in relation to two separate ideological dimensions: left-right (economic relations) and liberal-authoritarian (social relations).

A BSA report, ‘One-dimensional or two-dimensional? The changing dividing lines of Britain’s electoral politics’, written by Professor Sir John Curtice, in 2024, explores how over recent years, the liberal-authoritarian divide has become much more important in understanding voting behaviour than it used to be.

The liberal-authoritarian divide is now equal in importance with the left-right divide, when it comes to understanding support for Britain’s political parties. This is a big change, as historically the left-right divide was the dominant dimension that underpinned support for the two traditional big parties, with ‘left-wing’ voters supporting Labour and ‘right-wing’ voters supporting the Conservatives.

The EU referendum was the trigger for the increase in salience of the liberal-authoritarian dimension when it comes to voting behaviour. Whether someone voted Leave or Remain was far more correlated with their position on the liberal-authoritarian dimension than where they stood on the left-right axis. BSA data from 2016, indicated that there was a 51-point gap between the percentage of authoritarians who voted Leave (72%) and the percentage of liberals who did so (21%). In contrast, there was just a 7-point gap between those of a left-wing disposition who voted Leave (52%) and those of a right-wing disposition (45%).

Ironically, for a time, it appeared that this increase in the salience of a second attitudinal dimension may contribute to a resurgence of two-party politics, with the 2017 and 2019 general elections seeing the highest combined Conservative and Labour vote shares for many years.

As well as each of the two major parties continuing to dominate one side of the left-right divide, in these immediate post-Brexit years, they also managed to consolidate support among separate sides of the liberal-authoritarian divide.

By the time BSA data was collected in 2020, Labour had the support of 49% of left-wing voters and a commanding 35-point lead over the Conservatives among this group, as is traditionally the case. However, they also had the support of 47% of liberal voters and a 34-point lead over the Conservatives, something altogether new.

It was a mirror image on the other side of politics, with the Conservatives having the support of 54% of right-wing voters and a 37-point lead over Labour but also dominating among authoritarians, with 49% support and a 28-point lead over Labour.

As it turns out, it looks like the ability of the two traditional parties to retain and contain mass support, in an era of salient multi-dimensional attitudinal divides, was a short-lived one. BSA data collected in 2025 indicates that this has now broken down spectacularly, as can see by looking at each ideological segment in turn.

Firstly, if we look at party support among authoritarians, the Conservatives commanding position has been smashed and it is now the insurgents of Reform UK who enjoy the most support among authoritarians (34%), with a 16-point lead over the Tories.

Next, if we look at right-wing voters, we can see that although the Conservatives have retained their position as the largest party, their level of support among this group (26%) is half of what it was in 2020 and they have just a five-point lead over Reform UK.

Moving to the other side of politics, Labour continues to be the best supported party among both liberal voters and left-wing voters but in both cases support is down sharply compared to 2020, at 32% and 30% respectively. Among both groups, it is another insurgent party, the Greens, who are in second place, on 17% in each case.

With two challenger parties able to win significant support among ideologically defined sections of the population and with all parties having to compete across two highly salient attitudinal divides, it feels unlikely that we will see a return to traditional two-party politics any time soon.