New York CNN Business  — 

Americans aren’t the only ones obsessed with next Tuesday’s vote.

British bettors are wagering a record amount of money on the US presidential election, dwarfing the amount wagered on any sporting event or even their own nation’s politics.

As of Wednesday morning, £220 million, or about $284 million, had already been wagered on the Betfair Exchange, said Darren Hughes, a spokesman for Betfair. The London-based company operates the world’s largest online betting exchange.

Americans can now legally wager on sporting events in many states, but it’s illegal to wager on elections, either here or in the UK.

The amount of money wagered on this year’s US election already tops the previous record of the £199 million bet on the Trump-Clinton race four years ago. The greatest bet on any UK election was the £113 million on the 2016 Brexit vote.

Betfair is predicting the amount wagered for the US election will ultimately top £400 million.

“You can’t overestimate how big the president’s profile is in the UK. The betting interest has extended beyond political gamblers,” said Pete Watt, public relations manager for OddsChecker US, which provides advice and information to gamblers.

The betting will continue until a clear winner is announced, said Hughes.

“If, as some have predicted, the counting goes on for days or even weeks, we will continue to leave the market open,” Hughes said.

Betfair is one of several exchanges in the UK, though it is the largest, said Watt. Other exchanges and various sports books are also taking bets, which means the amount wagered could be even greater than the £220 million figure, Watt said.

The amount wagered on the US election to date is more than the combined wagering on Betfair for the four most bet-upon sporting events: the 2017 Floyd Mayweather Jr. vs. Conor McGregor boxing match, the 2018 World Cup, the 2019 Grand National horse race and the 2020 Super Bowl.

In the presidential race, those taking their chances on President Trump are getting much better odds. A £10 bet on the incumbent will return a profit of £18.80 if he wins, versus £5.26 on challenger Joe Biden — essentially giving Trump a 34.8% chance of winning.

Still, those are better odds for the president than some US forecasters are giving him. As of Friday morning, the political prediction site had Biden with an 89% chance of winning the vote.

Watt said the long odds on Trump are pulling in a lot of people who are betting on the president. Twice as many individual bettors are putting their money on Trump than on Biden, he said — though more money, and larger bets, are being wagered on Biden.

The winning bet will be who becomes the next president, not who wins the popular vote.

The wagering on this year’s election started with the presidential primaries, with odds on the many Democratic candidates constantly changing. After Biden finished a distant fifth in this year’s New Hampshire primary, the odds available to bet on him stood at 100-to-1, Watt said.

British bettors are already wagering on the 2024 presidential election, with the odds giving Biden and Vice President Mike Pence equal 16.7% chances of being elected president that year.

Democratic Vice Presidential nominee Kamala Harris is next with a 14.3% chance based on current odds, followed by Rep. Alexandria Ocasio-Cortez, with a 5.9% chance, Watt said. After that comes former South Carolina Governor Nikki Haley with a 5.3% chance.

And the odds give President Trump — if he loses this year — a 4.8% chance of being elected again in four years. If that happens, he wouldn’t be the first president to serve non-consecutive terms: Grover Cleveland did that as the nation’s 22nd and 24th president.