LONDON (MarketWatch) -- Wonder if the world is really paying attention to the U.S. presidential election? Look no further than Britain's betting parlors.

The U.K. gambling industry is expected to rake in around 5 million pounds ($8.1 million) in bets tied to the 2008 U.S. elections, said Robin Hutchison, a spokesman for Ladbrokes (LAD), Britain's largest gambling firm. That's more than double the amount wagered in 2004.

Others have estimated U.K. bookmakers could take in as much as 10 million pounds.

That doesn't rival an event like the Grand National -- Britain's premier horse race attracts bets totaling around 250 million pounds -- but it is on par with betting seen in a typical British general election.

The historical implications of the election have fed near-saturation coverage of the U.S. presidential race, starting with last winter's primaries and caucuses, in the British media, Hutchison said.

Plus, "it's not just an election in the United States; it's the election for the leader of the free world ... because it just affects so many countries around the globe," Hutchison said. "We take bets in 120 countries, and we've taken bets [on the presidential election] in all those countries."

Of course, British gambling shops are well-known for taking a wide variety of bets. And British gamblers are far from novices when it comes to wagering on U.S. elections.

More than 110 years ago, a London correspondent for the New York Times reported intense interest in the contest between Democrat William Jennings Bryan and Republican William McKinley.

"The Stock Exchange was the scene of unusual excitement today, more time being devoted to betting on the result of the presidential election in the United States than in the conduct of legitimate business," the Times reported.

“ 'It's not just an election in the United States; it's the election for the leader of the free world.' ” — Robin Hutchison, Ladbrokes

London's oddsmakers proved reliable, with McKinley, the victor in the 1896 election, favored 4-to-1 over Bryan.

Going into Tuesday's election, Republican John McCain is much more of a longshot than was famed orator Bryan.

Ladbrokes was offering odds of 13-2 on a McCain victory. A win by Democrat Barack Obama offers a meager payoff, with the Illinois senator a 1-in-12 favorite. In other words, a gambler would have to bet 12 pounds on Obama to win one pound if the Democrat is the victor.

Meanwhile, political futures markets, which have a strong track record in recent elections, also cast Obama as the heavy favorite. See full story.

While British bettors can lay wagers in any of thousands of local betting shops, U.S. gamblers must turn to political futures markets operated by offshore firms such as Intrade, or take positions in the Iowa Electronic Markets, which opened in 1988.

In a recent paper, economists Paul W. Rhode of the University of Arizona and Koleman Strumpf of the University of Kansas noted that political betting markets were common features of U.S. presidential elections from just after the Civil War until the 1940s.

And such organized betting markets were hardly an American invention. The scholars found that quotes of odds on papal succession appear as early as 1503, noting that such wagering was already considered an "old practice" at that time.

And in England, wagering on a myriad of political events predates American independence, they found. One historian, writing in 1880, noted that as far back as the late 1600s, "foreigners had observed that, on matters great and small, the only sure test of English opinions was the state of the odds."