Giving the British public a Final Say on Brexit through a new referendum is the most popular path if Theresa May‘s deal is rejected by MPs, a new poll has revealed.

An exclusive survey for The Independent shows that a fresh vote received more support than any of the four other options put to the public, including allowing the prime minister to go back to Brussels or a no-deal Brexit.

The survey by poling organisation BMG Research also suggests that more people oppose Ms May’s deal than back it, although the prime minister can take some comfort in the data showing a softening of opposition.

It comes amid growing speculation that the UK will have to delay Brexit to plot a fresh course, with some MPs and ministers pushing for the Commons to hold “indicative votes” on every possible option to test which carries majority support.

More than 1.1 million people have backed The Independent’s campaign for a Final Say vote on Britain’s exit from the EU since it was launched in June, with hundreds of thousands of supporters attending a rally in London.

As Ms May braces for a historic defeat on her deal on Tuesday, new polling shows that the public is riven with the same deep divisions held by MPs.

Some 46 per cent favoured a second referendum when BMG asked more than 1,500 respondents for their views on different outcomes should Ms May lose the vote. It found 28 per cent were against and 26 per cent did not know.

Remaining in the EU was backed by 45 per cent, while 39 per cent of people said they opposed reversing Brexit and 16 per cent said they did not know.

Forty-five per cent supported further negotiation with the EU, while 34 per cent were against going back to Brussels for fresh talks. More than a fifth (21 per cent) did not know.

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Some 40 per cent would opt for Norway-style deal – which allows access to the single market – but 36 per cent dismissed the option and 24 per cent were unsure.

Leaving the EU without a deal was the least popular option as it was preferred by only 35 per cent, while 45 per cent opposed it and 21 per cent said they did not know.

It comes as the prime minister has been reaching out to Labour MPs and trade unions in a last-ditch bid to get her deal through parliament.

Government insiders are expecting Brussels to offer Ms May some extra help by Monday, which they hope will ease fears from wavering MPs over the Irish backstop.

However, she is unlikely to secure a legally binding guarantee that the UK can independently decide to the leave the backstop, which Brexiteers and her DUP allies want.

BBC analysis estimates Ms May could lose the meaningful vote by 228 votes next week, after which she would have to come back to parliament within three days with a plan B.

Opposition to Ms May’s deal has weakened among the public, as the BMG research shows 37 per cent think MPs should reject the deal, compared with 43 per cent in December.

When asked if parliament should vote to accept the terms of the deal, 29 per cent said they should, up from 26 per cent last month. More than 30 per cent said they were unsure in both instances.

The poll put Labour and the Conservatives neck and neck on 36 per cent of the vote, with the Liberal Democrats on 12 points, Ukip on 6 per cent and the Greens on 5 points, once don’t-knows were excluded.

The Independent revealed on Friday that Ms May’s chances of delivering Brexit on 29 March are fading fast after senior ministers privately admitted more time is needed, even if her deal wins the backing of parliament.

On Saturday, transport secretary Chris Grayling was accused of engaging in “gutter politics” when he warned that blocking Brexit could lead to a surge in far-right extremism.

Police separate clashing Brexit protesters outside Parliament Show all 11 1 /11 Police separate clashing Brexit protesters outside Parliament Police separate clashing Brexit protesters outside Parliament Anti-Brexit protester Steve Bray (left) and a pro-Brexit protester argue as they demonstrate outside the Houses of Parliament Getty Images Police separate clashing Brexit protesters outside Parliament A pro-Brexit protester argues Getty Images Police separate clashing Brexit protesters outside Parliament Police surround the pro-Brexit protester after he confronted Steve Bray, a pro-European protester Getty Images Police separate clashing Brexit protesters outside Parliament A leave supporter is spoken to by a police officer as he argues with a remain supporter, Steve Bray, outside Parliament PA Police separate clashing Brexit protesters outside Parliament MPs in Parliament are to vote on Theresa May's Brexit deal next week after her December vote was called off in the face of a major defeat Getty Images Police separate clashing Brexit protesters outside Parliament A leave supporter is spoken to by a police officer PA Police separate clashing Brexit protesters outside Parliament Police look on as anti-Brexit protesters demonstrate outside the Houses of Parliament. Getty Images Police separate clashing Brexit protesters outside Parliament Police hold back a leave supporter PA Police separate clashing Brexit protesters outside Parliament A police officer speaks with anti-Brexit protester Steve Bray Getty Images Police separate clashing Brexit protesters outside Parliament Police surround a pro-Brexit protester after he confronted a pro-European protester Getty Images Police separate clashing Brexit protesters outside Parliament Conservative MP David Davies, wearing a gopro camera, speaks to anti-Brexit protester Steve Bray Getty Images

He urged MPs to back the Ms May’s deal, claiming reversing the decision to leave the European Union would “open the door” to “extremist” populist political forces and lead to divisions not seen since the English Civil War.

Meanwhile, two of the biggest donors to the Leave campaign said they believed Brexit would eventually be abandoned by the government.

Billionaire businessman Peter Hargreaves, who handed more than £3m to the exit campaign, said: “I have totally given up. I am totally in despair, I don’t think Brexit will happen at all.”