New study reveals that 77% of British voters now see themselves as centrist or right of centre – and that only 20% believe Jeremy Corbyn shares their position

Three times as many voters now regard themselves as on the centre ground or to the right of British politics as those who see themselves as on the left, according to a major survey of British public opinion in the aftermath of the Brexit vote.

A survey by Opinium and the Social Market Foundation, which asked people to assess their own political leanings and judge where they see party leaders on the spectrum, offers grim reading both for Jeremy Corbyn and those looking to displace him and build a wider coalition that can challenge the Tories in 2020.

The survey and accompanying report, entitled “Dead Centre? A review of the political landscape after the referendum”, not only shows those identifying themselves as on the right to be more numerous, but also demonstrates that they are more united in their views on the most burning political issues – including immigration and Brexit – than those on the centre and left.

Ominously for Corbyn, the polling, to be released on Wednesday before the party conference season, found that while 77% of voters place themselves as somewhere near the political centre (centre left, centre or centre right), only 20% believe the Labour leader occupies any of that territory, with 47% regarding Corbyn as solidly leftwing.

By contrast, Theresa May is seen as on, or close to, the centre ground by 43% of voters, and is described as rightwing by only 28%. After two months as prime minister, May is also viewed as marginally to the left of David Cameron (who styled himself as a centre-ground, modernising Conservative). Her chancellor, Philip Hammond, is also regarded as less rightwing than his predecessor, George Osborne.

Even on the controversial issue of expanding the number of grammar schools, May can take cheer from the polling, with 38% of all those questioned saying they supported the policy, against 21% who opposed it.

While the findings are not encouraging for Corbyn and will be little more so for his challenger Owen Smith, who is mounting his challenge from a broadly leftwing platform, they also show the difficulty that any alternative Labour leader would have in trying to build a broad coalition capable of winning elections again.

Emran Mian, the director of the Social Market Foundation, said of the findings: “Our polling and analysis highlights the problems facing Labour – not only is the broad centre-left and left smaller than the broad right, its constituent groups diverge on key issues like immigration and internationalism.”

The groups that Labour would need to bring together are split on policy and divided geographically, with the party’s target voters in working-class areas of the north and the Midlands having different worldviews to those in predominantly metropolitan southern areas.

Mian added: “The last time an enduring, successful electoral coalition was assembled from the centre-left was before the increase in immigration which took place in the mid-2000s, and one wonders whether another can be put together while the issue of immigration retains its current salience.”

By asking detailed questions on policy as well as identifying how voters see themselves, Opinium has identified eight “tribes” of voters. It placed 50% of the electorate in two tribes on the right (called Common Sense and Our Britain). With this support alone, its joint report with the thinktank says, the Tories could “aim for the 40% to 42% of the vote, which normally guarantees a healthy majority under our electoral system”.

But outside these two tribes – including, crucially, among potential floating voters on the centre ground and left – it found divergent views on everything from taxation to Europe, the future of the welfare state and equality. Another group identified as Progressives accounts for 11% of voters and is defined as a “scattering of professionals from across the UK”. They are comfortable with immigration, believe in the welfare state and would have to be courted as part of any centre-left coalition of interests. But the Progressives are at odds with another group defined as being to their left and entitled Community. This group is described as mainly made up of working-class voters from the north and Midlands who are sceptical of business and capitalism and are in many cases not internationalists.

The report, to be launched at a cross-party event attended by the Liberal Democrat former deputy prime minister Nick Clegg, the Tory former education secretary Nicky Morgan and Labour’s Chuka Umunna on Wednesday, says the number of diffuse groupings on the left and centre left reflects Labour’s huge electoral challenge.

“The groups ... are smaller in aggregate terms and are more fissiparous [than those on the right]. In particular, the groups on the left are split in relation to immigration, with the Solidarity group of older and poorer voters at odds with the Progressives and Democratic Socialists.”

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Umunna, a former shadow cabinet member, said of the poll findings: “They show that under the first-past-the-post system, if you want a left-of-centre government, then Labour is the only answer – but we can only achieve that by building a broad-based coalition spanning from the centre to the centre left. This work shows why if we reduce the party’s appeal down to a narrow left spectrum, we are doomed to failure and will be unable to make real our Labour values in office. Labour leaders through from Clement Attlee to Ed Miliband realised this.”

Opinium, which conducted its survey among a sample of more than 2,000 people in mid-August, found opinion on Brexit had not shifted at all since referendum night, with 52% backing leaving the EU and 48% wanting to remain.

The report adds: “The centre is not dead, not rhetorically anyway. People are still more likely to identify with the centre ground than one of the wings in politics. This suggests that there is a dividend to be gained from identifying as a centrist. “But what should a centrist politician do in order to sustain the support of voters? From our analysis of the tribes, it is easier to hold together a winning coalition, broadly speaking, on the right or centre-right than on the left.”

With Labour struggling to chart a way forward, leading figures from the Liberal Democrats, Greens and Labour, including the Green MP Caroline Lucas, Labour’s Lisa Nandy and the Lib Dem leader Tim Farron, published a book last week, The Alternative, calling for a wider “realignment of minds” and co-operation between progressive parties to take on the Tories.

Its editor, Chris Bowers, said: “The more we can seek common ground across the progressive spectrum, the more it could defuse some of Labour’s problems. If we can forge a broad progressive movement with clear but respectful liberal, green, social-democratic and socialist voices, we can celebrate the differences rather than see them as a drawback.

“The old certainties have gone now, the 2015 election and 2016 referendum results mean we have to see voters through new eyes, and only a willingness to explore new ways of working together will stop the Conservatives having a clear run at the next election.”