The public no longer believes it is necessary to leave the EU to control immigration in an extraordinary turnaround since the Brexit referendum, a survey has found,

Voters – including Leave supporters – said they now judge that existing EU rules provide “enough control” on incomers from the continent, without the need for the UK to pull out.

Far from demanding an immigration crackdown, no less than 71 per cent support allowing EU migrants to come to the UK either to work or study – including 62 per cent of Leave voters from 2016.

The results represent a striking shift from three years ago, when a widespread anti-immigration sentiment fuelled the Brexit vote, rather than a general revolt against the system as many politicians claimed.

Crucially, the researchers at University College London put it down to “missing information” – because so many people were unaware about the existing controls back in 2016.

Just 20 per cent knew about the “three-month rule”, the EU regulation – never enforced by the UK – requiring any EU citizen seeking to stay beyond three months to work, study or have enough money to support themselves.

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And only 13 per cent were aware the UK could require EU citizens to register where they live, as some other EU countries do, to track those not meeting the strict conditions.

Instead, no less than 47 per cent of respondents wrongly believed there were no possible restrictions on EU immigration – including 58 per cent of Leave voters and 62 per cent of pensioners.

The poll will therefore fuel arguments for a Final Say referendum on the Brexit outcome, because – just as in the vital area of cross-border trade – voters now have fresh knowledge.

Diane Abbott, Labour’s shadow home secretary, said: “Too many politicians are whipping up fear of immigration for purely political advantage.

“But once voters know about the controls available under existing EU rules they are largely content.”

And Christine Jardine, the Liberal Democrat home affairs spokesperson, hailed the survey as evidence that “British people recognise the huge benefits of EU free movement”.

“It gives us all the opportunity to study, work and retire anywhere in the EU. And EU citizens make enormous contributions to our society, economy and culture,” she said.

Back in 2016, voters were blitzed by hardline anti-immigration messages such as Vote Leave’s notorious stoking of fears about Turkish immigration by claiming the Muslim country could join the EU by 2020.

In the days before the referendum, Nigel Farage unveiled his inflammatory “Breaking Point” poster of desperate refugees, which was condemned as akin to 1930s fascist propaganda.

Once informed about the immigration controls the UK could be introducing already, public opposition to EU rules falls away dramatically, the poll found.

Almost two-thirds of those surveyed (64 per cent) said the “three-month rule” would provide “enough control” over EU immigration, including most Conservatives (61 per cent) and most Leave supporters (58 per cent).

Dr Alan Renwick, the deputy director of UCL’s Constitution Unit, said: “These results suggest that a majority of British adults would be content with a system that enforced all the controls available to it on EU immigration.

“When it comes to accessing the single market and controlling immigration, it may be that the choice is not such an either/or one as is often supposed.”

And Dr Lee de-Wit, director of the political psychology lab at Cambridge University, pointed to the huge attention given to “misinformation in political campaigns”, adding: “This poll highlights the simpler phenomenon of ‘missing information’.”

The survey, of more than 1,000 British adults, carried out by YouGov between 20 and 30 August, builds on previous polls finding remarkable changing attitudes towards immigration.

In April, an Ipsos Mori survey for the BBC, found it was a concern for only 11 per cent of people – the lowest level since 2001.