The co-founder of clothing label Superdry has made a record donation to the campaign for a referendum on the final Brexit deal.
Julian Dunkerton has given £1m to the cause, saying: "I've got a good instinct for when a mood is going to change and we're in one of those moments now."
His words come as Brexit Secretary Dominic Raab prepares to head to Brussels on Tuesday to speed up talks with the European Union's chief negotiator Michel Barnier.
And on Thursday, the first in a series of technical notes will be published to help people and businesses prepare for a "no deal" Brexit if there is no agreement between the UK and EU.
Ahead of another key week in the Brexit process, Mr Dunkerton told The Sunday Times that the public know Brexit will be a "disaster".
He said: "I'm putting some of my money behind the People's Vote campaign because I know we have a genuine chance to turn this around."
Mr Dunkerton added: "I will be paying for one of the most detailed public polling exercises ever undertaken by a campaign, so more of us have the confidence to demand the democratic right for our voices to be heard - to get a People's Vote on any Brexit deal."
Mr Dunkerton co-founded Superdry, famous for its hoodies and t-shirts, in 1985 from a market stall in Cheltenham and there are now more than 500 outlets in 46 countries.
Superdry floated on the London Stock Exchange (Other OTC: LDNXF - news) in 2010 and he said that if Brexit had happened 20 years earlier, the company "would never have become the global success that it is".
Tom Baldwin, from the People's Vote, said the Superdry boss "senses there is a big shift coming in Britain" as voters are fed up with the way politicians have been dealing with Brexit.
He told Sky News: "Our campaign wouldn't exist, Julian Dunkerton wouldn't be giving us money, normal people wouldn't be flocking to us now if this was going well - but Brexit is turning out to be a disaster.
"In those circumstances, when the politicians have made a mess of it, it's the most democratic thing in the world to say let the people have a vote.
"People are seeing, from every walk of like, from every part of the country, that Brexit is turning out to be a disaster, it's not what we voted for - whether you voted leave or remain, we're having a car crash here.
"It can't be left to politicians in Westminster who have shown over the past two years they are incapable of designing a Brexit which works for everyone."
Mr Raab insists securing a deal is "still by far the most likely outcome" and it is hoped that an agreement could be reached at a summit in October.
But nearly £4bn has been allocated by the government to prepare for a no-deal scenario.
"We are committed to ensuring continuity and stability for citizens and businesses across the entire UK," Mr Raab said.
Preparing for a no-deal scenario, he said, is "the responsible thing for any government to do, to mitigate the risks and make sure the UK is ready to make a success of Brexit".
Both sides of the debate have been stepping up their campaigning, however, and Theresa May faces a split within her own party as she seeks approval for any final agreement.
Brexiteers have said they are against any agreement which keeps Britain tied to the customs union or single market but The Sunday Telegraph reported that the government is planning to recognise some EU rules if there is a no-deal Brexit.
This would mean taking a "flexible" approach to ensure the availability of medicines, car parts and chemicals.
A spokesman for Number 10 did not comment on the report.