Regardless of who is elected president in 2016, it is becoming clear that there is already one big winner. Namely, British bookmakers.

Betting on the presidency is turning into a sizable and growing business on the other side of the pond. The 2012 contest generated £10 million (approximately $15 million) in wagers, according to William Hill, a leading bookmaker. And expectations are high that the wagers on the 2016 election will top that, say industry insiders.

Part of what’s driving interest is the possibility of a Clinton-Bush rematch, albeit with a different Clinton (as in Hillary) and a different Bush (as in Jeb). William Hill has Clinton as the favorite to win the presidency, with odds of 5-to-4 (meaning for every 4 pounds wagered, you’d win 5); Bush comes in next at 4-to-1. (Paddy Power, a bookmaker in Ireland and England, has Clinton at 6-to-5 and Bush at 5-to-2.)

But another part of the fun is that the field is still so wide open — at least on the Republican side — and that generates both buzz and betting. William Hill is also taking wagers on the suddenly hot Scott Walker (his odds have gone from 33-to-1 to 10-to-1 in recent weeks), plus Marco Rubio (14-to-1), Rand Paul (14-to-1) and Chris Christie (25-to-1).

And what if Clinton decides not to run? That could generate only more interest in the race, say bookmakers. As it is, William Hill is already taking wagers on Elizabeth Warren (18-to-1) and Joe Biden (33-to-1).

Of course, all this gambling isn’t taking place in America, where betting on political races is generally not allowed by law, despite recent attempts to change that fact. British bookmakers also say they won’t accept political bets made via the web from America — online gambling is, to put it mildly, a thorny matter. Still, they say there are plenty of Britons — and expat Americans living in the United Kingdom — who are interested in wagering on who will become president. In fact, wagering on the U.S. race surpasses wagering on the U.K. prime minister contest, say bookmakers.

Paddy Power says it has already taken in 5,000 wagers on the 2016 election, even though Election Day is more than a year away. In pounds (and dollars), that equates to a “chunky six figures,” says Rory Scott, a spokesman for Paddy Power.

Scott adds that what’s driving gamblers’ interest in the 2016 election is more than the candidates themselves. Regardless of who’s running, the race for the White House has become a global obsession. “It’s a modern-day sports contest,” he says.

But that is not to say British bookmakers can’t have a little fun with the contest. Most are taking bets on celebrities and other prominent figures who seem unlikely to run for president anytime soon. William Hill has odds on Oprah Winfrey (100-to-1), Lady Gaga (250-to-1) and even Tiger Woods (1,000-to-1).

“We have taken some substantial bets” on the golf champ, says Graham Sharpe, a spokesman for William Hill.