If those suffering from post-referendum “Bregret” had voted to stay in the European Union, the outcome of the Brexit vote would have been in favour of Remain, according to new analysis published by the British Election Study.

In a poll of more than 10,000 voters, the study found 1% of Remainers regretted their choice, in contrast to 6% of Leavers.

The study lends credibility to the theory that many exercised a protest vote in the referendum as a way of hitting back at the Westminster elite.

Economist Iain Begg, from the London School of Economics, said the results exposed the shortcomings of using referenda in complex policy choices.

“The finding that a sizeable proportion of Leave voters now regret their decision, coming barely one hundred days after June 23, highlights the shortcomings of using referenda to make policy choices on issues as complex as membership of the EU,” he told The Independent.

Both Remain and Leave voters expected that their side would win (British Election Study)

“Even without this ‘buyer's regret’, the 17.4 million votes for Leave amount to only 37% of the 46 million registered electorate, however, Theresa May's government is adamant that it will not re-open the matter.”

The study also found Leaver remorse to be strongest among those who didn’t expect their side to win, with one in ten regretting their Brexit vote.

A High Court legal challenge against Brexit will enter its second day on Monday, which will make the case against the Government's right to trigger Article 50 without parliamentary approval.

The challenge will hear whether Theresa May has the power to take the UK out of the EU without MPs voting on it.

Those expecting to lose were more likely to regret their vote (British Election Study)

The case has been brought forward by Gina Miller, an investment banker, among others.

She said using the royal prerogative, the process by which the government on behalf of the sovereign can conduct foreign affairs and enter into international treaties, would set a dangerous precedent.

“I’m questioning whether the Government has the right to bypass Parliament and use this royal prerogative, which they are still saying that they do and that she does, and that she and a handful of ministers will be able to trigger Article 50 without any sort of legal certainty or scrutiny in Parliament,” she told Audio Boom.