Hillary Clinton may be soaring ahead in the opinion polls, but gamblers are far from counting out Donald Trump in the presidential race.

Just this Saturday, a speculator in southwest London put a £10,000 ($12,156) bet on the Republican candidate, prompting bookmaker William Hill WMH, +6.60% to shorten its odds on the businessman becoming the next U.S. president. Together with a series of smaller four-figure bets, the odds on Trump taking over the White House now stand at 9/2, or 18%, up from 11/2, or 15%, ahead of the weekend.

“It has been one-way traffic in the betting market for several days as we took bets on Hillary Clinton of €550,000 and £183,200, both from female customers, amongst many others, but now there is a swing back towards Trump,” said William Hill spokesman Graham Sharpe.

“Plus there is still some time and one debate to go, so there’s time for things to change drastically,” he added.

The £10,000 wager over the weekend marks the largest individual bet on Trump placed at William Hill, although it doesn’t represent the largest amount of money that could be won by one William Hill customer.

One gambler from Cornwall in southwest England stands to take home more than £100,000 if Trump wins, after placing 30 smaller bets on the Republican.

Overall, Trump has attracted about a third of the individual wagers at William Hill, but Clinton accounts for about 80% of the wagers in terms of the amount of money bet, Sharpe said.

The U.K. has a sizable gambling industry, and the U.S. presidential race has provided it with one of its biggest-ever political events to bet on.

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The string of Trump bets come even as opinion polls are showing a comfortable lead for the Democratic candidate. The latest NBC News/Wall Street Journal survey out on Sunday put Clinton 11 points ahead, while an ABC News/Washington Post poll gave her a four-point advantage.

But the clear lead for one side isn’t enough to convince gamblers about the outcome.

“This is exactly what the polls said about Brexit,” Sharpe said. “You are of course talking about U.S. polls, rather than British polls, but I think people have lost a bit of faith in the accuracy of polls.”

“This is a whole different ballgame. Normally pollsters are asking people who they like the most, but in this campaign — from what we can gather at this side of the pond — it’s more a matter of who they dislike the least.”

After the surprise Brexit result in the U.K. this summer, pollsters and bookies have been criticized for inaccuracy. Just a few day ahead of the June 23 referendum, bookies were showing a more than 75% chance of the Brits voting to remain in the EU, while opinion polls had pointed to a small win for the remain side.

Also in the U.S., statisticians have struggled to predict the election outcome. Election-predictions prophet Nate Silver, for example, insisted for months that Trump would have no chance at winning the Republican nomination, which, of course, turned out to be completely wrong. Silver and his FiveThirtyEight team now predict an 86% of Clinton winning the election, but stress that the degree of undecided voters remains fairly high.

The considerable uncertainty is one reason why bookies expect bets to soar in coming weeks, as the Nov. 8 election draws closer. The betting industry in the U.K. has already seen between £12 million to £15 million placed on election bets and the final tally is poised to be around £20 million, Sharpe estimated. That would make it the biggest-ever turnover for a U.S. election.

“Traditionally on political events people want to wait until as late as possible to know all the latest information,” he said. “We expect to see a big rush closer to the time, and particularly depending on what happens at the final debate.”

The third and final debate takes place on Wednesday.