The co-founder of British clothing brand Superdry has donated £1m ($AUS1.7 million) to the campaign for a referendum on the final Brexit deal.
Multi-millionaire Julian Dunkerton, a "remainer" who opposes Britain's planned departure from the European Union, said he was backing the People’s Vote campaign because he saw a “genuine chance to turn this around”.
"I've got a good instinct for when a mood is going to change and we're in one of those moments now," he said.
The UK voted to leave the EU in a 2016 referendum and is scheduled to depart on 29 March next year.
London and Brussels hope to agree a Brexit deal at a summit in October but Prime Minister Theresa May faces splits within her party and the tough task of securing parliamentary approval for the final agreement.
The People's Vote, a cross-party group including some MPs, want a public vote on the final Brexit deal.
Mr Dunkerton's donation is the largest received by the People's Vote and will help to fund opinion polls.
He claimed that Superdry would never have been a success if Brexit had happened 20 years earlier.
Could a second referendum happen?
MPs could vote against the exit deal between the UK and EU, which would set the UK on course for leaving the bloc without any formal agreement on what happens next.
Anti-Brexit MPs hope this scenario would see enough support generated for a second referendum to take place.
However, Mrs May has previously said a second referendum should not be held during the Brexit process.
While Leave won the initial vote 52 per cent to Remain's 48 per cent, when voters were asked in a YouGov poll whether there should be a referendum on the final terms of any Brexit deal, 42 per cent said there should be a fresh vote while 40 per cent said there should not. The rest did not know.
On Saturday, the former leader of the United Kingdom Independence Party Nigel Farage said he would join a "battle bus" tour around the country by a pro-Brexit group which is opposed to Mrs May's plans, arguing it makes too many concessions to Brussels.
Both Britain and the EU have said they want to avoid a damaging "no deal" outcome which would be particularly harmful to businesses.
