The UK would vote to stay in the European Union by 54% to 46%, according to a major poll of 20,000 people.

The poll, the biggest of its type since the 2016 referendum, suggests a significant shift in public opinion towards reversing the result of two years ago and staying in the EU.

105 local authorities that voted Leave in 2016 would back Remain in another vote, the research says.

These areas include Birmingham, Nottingham and Luton in England, plus Swansea in Wales.

Pro-EU MPs call on Theresa May to listen to the findings and hold another referendum.

LONDON — The United Kingdom would vote to stay in the European Union in a new Brexit referendum, with over 100 local authorities that backed Leave in 2016 switching to Remain, according to a new poll of 20,000 people.

Survation has carried out the biggest public survey on Brexit of its sort since the referendum, using the methods that helped the few pollsters who correctly predicted a hung parliament at last year's general election.

The poll, revealed by Channel 4 on Monday night, found that in another referendum on Brexit, 54% of people would vote for the UK to stay in the EU, while 46% of people would vote to stick with the 2016 decision to depart.

The research says 105 local authorities that voted for Leave in 2016 would vote for Remain in a new referendum.

These include Nottingham, where just 40.1% of people would vote for Brexit after 50.8% of people there voted for it in 2016, and Luton, where the 56.5% Leave vote in 2016 would drop to 43.8% in another referendum.

Overall, the poll found that support for leaving the EU has decreased the most in areas which delivered the largest Brexit votes in 2016, suggesting a significant shift in public opinion as Britain heads for the EU exit door.

The pollsters are "very confident" that the following local authorities have switched from Leave to Remain:

Nottingham (40.1% Leave now but was 50.8% Leave then)

Luton (43.8% Leave now but was 56.5% Leave then)

Slough (41.6% Leave now but was 54.3% Leave then)

Southampton (41.8% Leave now but was 53.8% Leave then)

High Peak (44.3% Leave now but was 50.5% Leave then)

Watford (43.6% Leave now but was 50.3% Leave then)

Canterbury (44.6% Leave now but was 51% Leave then)

Cherwell (44.5% Leave now but was 50.3% Leave then)

Reigate and Banstead (44.9% Leave now but was 50.5% Leave then)

Knowsley (39.7% Leave now but was 51.6% Leave then)

North Tyneside (45.5% Leave now but was 53.4% Leave then)

Birmingham (41.8% Leave now but was 50.4% Leave then)

Sutton (44.9% Leave now but was 53.7% Leave then)

Isle of Anglesey (44.2% Leave now but was 50.9% Leave then)

Swansea (43.2% Leave now but was 51.5% Leave then)

Rhondda Cynon Taf (43.5% Leave now but was 53.7% Leave then)

This major piece of research comes as Theresa May faces increasing pressure from MPs and business leaders to put the outcome of Brexit negotiations to another referendum, or what campaigners call a "People's Vote."

Over 70 business leaders including the head of Waterstones and former Sainsbury's boss Justin King have signed a letter calling for another referendum, while the number of MPs who support the campaign has increased in recent weeks.

A senior People's Vote source told Business Insider last week that up to three Conservative MPs were set to join the campaign for another referendum later this month.

Tom Brake MP — Brexit spokesperson for the Liberal Democrats and a supporter of the Best For Britain campaign against Brexit — told BI: "The will of the people is not set in aspic. This poll, the largest of its kind, shows that as Brexit unravels and the benefits of EU membership become clearer, the appetite for Remain grows.

"But there is only one way to test the scale of this change and that is through a People’s Vote."

Brake's Lib Dem colleague, Layla Moran MP, said the findings showed "unequivocally that the momentum behind a People’s Vote is now at breaking point" as negotiators try to make a breakthrough in Brexit talks.

"Theresa May needs to take responsibility for her botched Brexit. We need to give the People, who are clearly changing their minds, the final say," Moran told BI.

May has consistently ruled out holding another referendum, while the position of Jeremy Corbyn's Labour party is to consider backing another referendum if a general election in early 2019 isn't possible.

Negotiators hope to finalise a deal by December at the latest with the UK's March departure just five months away.

The Survation research suggests that most people would be willing to compromise in Brexit talks the EU.

For example, a majority back a liberal UK-EU immigration policy after Brexit, in which EU and UK citizens would be able to live and work in each other's countries (76%). They'd also support a deal in which the UK would follow EU rules on certain goods (62%), meaning the UK would stay close to aspects of the single market.

However, a large majority of respondents want the UK to have an independent trade policy after Brexit (75%).