As much as half the adult population may share a political world view researchers describe as "authoritarian populist".
They favour rolling back the state and are negative about immigration, human rights and the EU, a study claims.
It concludes these views are set to have a "huge effect" on decisions voters make at the EU referendum.
Many more people share this outlook than the four million voters who backed UKIP at the election, the work says.
Academics at the Universities of Essex and Exeter say theirs is the first attempt to analyse what they call "authoritarian populist" views in the Britain.
Politics professors David Sanders, Tom Scotto and Jason Reifler used data from a series of YouGov panel surveys conducted between 2011 and 2015 to reach their conclusions.
Mr Scotto said: "People like us academics and the London elite just shrug off concerns about immigration, they shrug off concerns about the decline of Britain as a military power.
"This is where I think some of animosity is coming from and the electorate is saying we count too."
The study - shared with BBC Radio 4's Today programme - measured the sentiment by assessing respondents' ideological sympathy for the market and rolling back the state; a "strong and tough" foreign policy; a negative emotional response to immigration; a critical attitude to human rights and disapproval of the European Union.
Analysis by Ross Hawkins
At Westminster they've long wrung their hands about voters who don't make much of the centre ground of British politics.
Some look anxiously across the Atlantic at Donald Trump's progress and wonder if a similar movement could happen here.
This study boasts it is the first systematic empirical analysis of the prevalence of a "mind-set" it dubs "authoritarian populist" in Britain.
It will cheer those campaigning for a Leave vote, although it doesn't guarantee them support.
Those on the Tory right will also seize on the work to argue the "modernisation" of the Conservative party under David Cameron has gone far enough.
The study is based on sifting through data from surveys of panels. It isn't a poll that makes certain claims within a margin of error about how the country will vote.
That, though, is in many ways the point. It tries to get behind the normal questions polling companies ask about voting to explore broader public attitudes.
Its findings are necessarily uncertain, but for some centrist politicians they will be uncomfortable too.
The study's authors found just over half of their sample could be characterized as authoritarian populists.
They conclude: "The analysis shows that there is a coherent set of beliefs, held by a surprisingly large proportion of the UK electorate, which can reasonably be described as authoritarian populist."
But Anthony Wells from YouGov stressed the study did not reveal half the population were certain to vote for a Leave vote at the referendum.
Not all of those classed as authoritarian populists said they opposed the EU.
Mr Wells said: "The majority of people have views that can be categorised as authoritarian but within that there are degrees.
"This isn't half the country are dyed in the wool Ukippers who want to pull out of Europe straight away, who want to stop immigration."