As we all know, fragmentation and volatility have barged their way into the political lexicon. We can all think of the disruptive events that have accompanied the current wave of political turbulence. But have they caused it?

Disruptive events are not new. Between 1950 and 1970, we had the Suez debacle, devaluation, Britain’s first attempt to join the Common Market and fierce arguments over gay rights, abortion and capital punishment. Dissidents took to the streets: right-wingers over race, immigration and the loss of empire; left-wingers over Vietnam, apartheid and nuclear weapons. 

Yet the Labour-Conservative duopoly sailed on regardless, buoyed by a tide of rising living standards. In each of the seven general elections held during those twenty years, both parties won 45% of the national vote, plus or minus just 4%.

Something fundamental has changed since then. In fact, two related things have changed. One has been widely observed: the collapse of the historic link between social class and political loyalties. In 1967, Peter Pulzer, one of the greatest post-war political scientists, said “class is the basis of British party politics; all else is embellishment and detail.” Labour voters were mostly working class and heavily unionised, while Tory supporters were mostly middle class. Nowadays class makes little or no difference to the way people vote, and unions are a much-diminished force. 

We can now add to the story. For six decades the bible of political science has been Political Change in Britain by David Butler and Donald Stokes. In their groundbreaking research in 1963 they found that a voter’s family background had a huge influence on their adult loyalties Among those who grew up with Conservative-voting parents, 75% were still Tory. In Labour families, the loyalty rate was even higher: 81%. Consistency, in terms of both family history and social class, provided the rock on which electoral stability was built.

Today, it is not just social class that has lost its power to sway votes. Family background also matters far less than it did. Fresh YouGov research, reported here for the first time, shows how its influence had declined by last year’s election – and has slipped even further since then:

Today, voters who grew up in Conservative-voting homes are more likely to vote Reform than Conservative – while among voters from Labour families, the equivalent figures are a statistical dead-heat: Labour 33%, Reform 32%. Indeed, the collapse in family influence is greater than that. The figures for both Labour and Conservative loyalty are now just a few points higher than those we would expect if family background had no influence at all.

One obvious conclusion is that in recent decades, voters have increasingly flown the family nest and chosen their own social identities and party loyalties. They are willing to think afresh and vary their vote with each election. Hence today’s volatility and fragmentation.

However, if identity, social class and family circumstance have little influence on the way people vote, what does?

To find out, YouGov offered a list of ten reasons people might have for supporting their current party. It then asked a) which were the two or three main reasons; and b) of those, which was the single most important reason.

These are the overall results:

Three reasons stand out ahead of the rest: “It isn’t great but it’s better than the alternatives”; “It shares my values”; “It has the best policy on the issue I feel most strongly about.”

The differences among the supporters of each party emerge when you look at the single most important reason people give, and classify each response as those of “devotees” or “consumers”:

These figures should terrify both Labour and the Conservatives. They cling to the hope that their current levels of support, around 24% and 18% respectively, represent their loyal core vote – people who are committed to the cause and can be relied on, come what may. 

YouGov’s figures offer no such relief. Both parties may seem to be in a valley with a mountain to climb; a more accurate metaphor is that they are on a ledge, in clear danger of falling further. In both cases, the single most important reason their supporters give for backing them is scarcely a vote of confidence: their party isn’t great, merely better than the alternatives. Altogether, well under half of Labour and Tory supporters declare their devotion to the cause. The Liberal Democrats do only slightly better. 

There is one crumb of progressive comfort. A year on from the general election, the willingness to vote tactically persists among useful numbers of both Labour and Lib Dem supporters. This helped them enormously last year. They may need it again to ensure a progressive majority at the next general election

The two insurgent parties – Reform and the Greens – have far more devoted voters than the three traditional parties: 61% for Reform and 71% for Green. The Greens score strongly on both values and the issue that most concerns its supporters. Reform’s supporters are different. Few of them are passionate about its values. It’s a specific policy area that concerns them.

No prizes for guessing what that is. But the poll contains one surprise, for me at any rate.

Just over 500 of YouGov’s 4,000 respondents cited a specific policy reason for supporting their party. Almost 300 of the 500 were Reform voters; the other 200-plus were divided among the other parties. We asked them to say what it was in their own words. Among the 82 Greens, 52 mentioned climate change; no single issue stood out among the 43 Conservative, 43 Labour or 38 Lib Dem supporters.

Reform voters have by far the clearest views. These were the answers given by their 295 respondents who ticked the “issue I feel most strongly about” box

• Immigration/boats/asylum seekers: 267 (including 94 who mention “illegal” or “boats”)
• British/traditional values / Make Britain Great again: 8
• Economy/benefits/public spending: 7
• Israel /Islamification: 3
• Others: 10

To me the surprise is what is not in that list. Buried among the ten “others” is the only mention of the campaign that has propelled Nigel Farage to prominence. This respondent wrote “Getting Brexit properly finished and getting the UK right away from the EU”. That this answer stood alone does not mean that Reform voters have stopped caring about Brexit – although other surveys do show that the enthusiasm of many of them has waned as the promised benefits of life outside the EU have failed to materialise. The larger point is that Farage has moved on, and so have his fans.

Back to the big picture: the two pillars of the old Labour-Conservative duopoly, family influence and social class, have crumbled, and nothing has replaced them. Stalled living standards add to their plight. Short-term judgements are replacing long-term loyalties. We shop around as never before. Expressions of lasting fealty can still be heard, but their echoes are growing fainter.

To say that votes today are increasingly matters of consumer choice is not to say it was solely about devotion in the past. Close elections always depend on floating voters who make up their mind for reasons that vary from election to election. 

But such consumer-voters used to be a minority. From 1950 to 1970, devotees comprised the great majority of Labour and Conservative voters. While elections were decided by the consumerist minority in between, both parties had a distinct character – a mixture of ideology, culture, values and class interest – which was reflected in both their policies and their large electoral base.

What now? Should Labour and the Conservatives seek to rebuild their bases of devoted followers – or accept that those days are over and that most voters, not just a minority, are now footloose consumers?

Rebuilding their bases would plainly help them regain their positions as Britain’s two dominant parties. If they could draw on their histories to provide alternative doctrines about how Britain should be run, this would also be the surest way to give voters at election time a clear choice of futures, not just of managers.

Is this possible? The results of our survey suggest that enthusiasm is greatest for parties, such as Reform and the Greens (and the SNP in Scotland), that have a specific brand rather than a proud past and a general offer of better government.

Here is my challenge to Labour and the Conservatives: if you wish to revive your duopoly, and recreate a politics of devotees and not just consumers, what distinctive doctrines can you offer? Claims of greater intelligence, honesty, competence and personal morality are off limits. We know that all parties include all sorts. No insults either. Rather, could leading Tory and Labour MPs come together and set out a shared definition of the principles that divide them?

I am not sure they could. In the past half century, politics has changed as much as the economy and the electorate. Without a revival of clearly defined rival doctrines, consumer choice will sweep away the vestiges of devotion and with it any hope of the old, stable duopoly returning. 

If first-past-the-post survives, it will continue to generate weird election results; and incoming governments, like Keir Starmer’s, will have fewer and fewer loyal devotees to sustain them when times get rough.

Peter Kellner is founder of YouGov. His substack can he found here