Theresa May would abandon Brexit if elected Prime Minister, Ukip donor Arron Banks claims

The Ukip donor and millionaire businessman Arron Banks says he does not believe Theresa May would push through Brexit if she were to become Prime Minister.

Mr Banks, a key financial backer of the Leave.EU campaign, has said he will back Andrea Leadsom in the Tory leadership race, primarily due to a fear the Home Secretary would ‘betray’ Brexit if elected leader.

Speaking on the BBC’s The Andrew Marr Show, Mr Banks said he believed Mrs May would be “the death of Brexit, by a thousand cuts”, and would “absolutely” betray the referendum result.

He claimed she may delay triggering Article 50 until it is too late, and circumstances have changed, or echo the Norwegian “political elite” – allowing free movement in exchange for access to the single market.

The Tory leadership frontrunner has stated she fully intends to trigger Article 50 if she becomes Primer Minister – probably by the end of the year.

Her campaign chief, Chris Grayling, also insisted there was "no question" of a second referendum on the EU if the Home Secretary wins, with the UK severing ties with Brussels before the 2020 general election.

He added that he was expecting EU citizens to be able to remain in the UK after Brexit, something Mrs May has refused to guarantee unless she receives a similar commitment from the other 27 member states about the future rights of Britons overseas.

"I don't think there will be any change on either side," he said. "Everyone will take a grown-up approach to this. It would be too damaging to do otherwise. However, we should always make sure that we look after the interests of our own citizens. I don't think anything is going to change."

He added: "I'm expecting all EU citizens, perhaps bar those who've committed criminal offences and ones with individual circumstances, to be able to stay as they do now. And I'm expecting UK citizens in other countries to be able to stay there too. That's right and proper."

He told the BBC's Sunday Politics she had stressed that "Brexit means Brexit" and added: "We think she has got the weight and the experience to deliver what people want."

When asked if he would consider putting himself forward to replace Nigel Farage as Ukip leader, Mr Banks said he had not yet decided.

“I haven’t discounted it completely,” he said.

If Mrs May were to win, Mr Banks said it is likely a new party could be set up, ready to take on both Labour and Tory parties.

He has said the prospective new party would be more online-focussed, and have more direct democracy.

“The elite have hated the referendum because it took the power away from them and actually I think this has been a wonderful thing.

“The idea of more referendum and going down the Swiss model [of direct democracy] would be fantastic.”

In Switzerland, any change to the constitution must be voted on in a public referendum. Referendums may also be requested for changes in law.

Mrs May promised on Thursday that she would be “bloody difficult” when it came to Brexit talks: “Ken Clarke might have found me to be a ‘bloody difficult woman’. The next person to find that out will be Jean-Claude Juncker,” she joked.

A recent survey conducted for The Independent has revealed British voters value the access to the single market more than they value capping immigration from Europe.

48 per cent of respondents, including 76 per cent of Remain voters, said they would sacrifice an immigration cap in exchange for access to the single market, compared to only 37 per cent who said limiting immigration was more important.