NFL wagers at all-time high in U.K.

The NFL's popularity is growing internationally, especially at the betting windows.

Sports books in the United Kingdom expect more money will be wagered on the NFL this season than in any other year. London's Wembley Stadium will host three games this fall, beginning with the Miami Dolphins and Oakland Raiders on Sunday. The books say they receive up to a 100 percent increase in the amount wagered on the NFL games played at Wembley Stadium compared to those played in the U.S.

Ladbrokes, one of the U.K.'s largest books, anticipates the uninspiring Dolphins-Raiders matchup will attract 10 times more betting action than it would if it took place in the U.S. U.K. sports book giant William Hill says it has seen a 75 percent spike in betting on past games played at Wembley Stadium.

Overall, the amount wagered on the NFL at William Hill has increased 40 percent year over year, according to company spokesperson Joe Crilly. The NFL began playing games in London in 2007. Two games were played last season at Wembley Stadium. This season, the three-game slate will continue with the Atlanta Falcons and Detroit Lions on Oct. 26, then the Dallas Cowboys and Jacksonville Jaguars on Nov. 9.

Sports betting is legal in the U.K., including online wagering. Even so, the NFL attempts to distance itself from the gambling that takes place on its games. Per league policy, on-site betting windows and kiosks at Wembley Stadium are closed during NFL games.

"In line with the NFL's policy on gambling, we have never had any betting outlets operational at our games at Wembley, regardless of operator," NFL spokesman David Tossell said in an emailed statement.

There are, however, more than 30 gambling parlors in the Wembley Park area, where the stadium is located. Judging by the increase in betting at the books, punters are not having trouble getting down a few pounds on their team of choice. This week, twice as much money had been wagered on the Dolphins at William Hill, but the Raiders had received more overall bets as of Wednesday.

Just like in the U.S., the matchups play a role in how much is bet.

"The Patriots are very popular with punters," Crilly said. "Although, the betting public is very clued up and rather than following a certain team, they will back who they think will win."

Last year, the biggest bet William Hill took on the Minnesota Vikings-Pittsburgh Steelers game was 600 pounds ($977). The biggest bet on the Dallas Cowboys-San Diego Chargers game was 4,000 pounds ($6,531). Both William Hill and Ladbrokes said that six-figure wagers on the NFL are rare. Bets in the five-figure range generally make up most of the bigger wagers.

"We may take slightly more in the way of big bets [on NFL games at Wembley Stadium]," Ladbrokes spokesman Alex Donohue said in an email, "but the main difference would be the sheer amount of bets placed."

While betting on the NFL in the U.K. is increasing, it still pales in comparison to the action on European soccer. Crilly said a televised Premier League game will attract 2-5 million pounds in wagers. The amount wagered on an NFL game is "very much smaller," he added. Ladbrokes says an NFL game attracts about 10 percent of what is wagered on a Premier League match.

Meanwhile in the U.S., the NFL has been fighting the expansion of sports betting. The NFL -- along with the NCAA, NBA, MLB, NHL and U.S. Department of Justice -- has been in a two-year legal battle with New Jersey to prevent the state from offering sports betting at casinos and race tracks. The leagues and the Department of Justice have until Monday to respond to New Jersey's latest attempt in a court case that's lasted for more than two years.

Here's a look at the past games held in the U.K., including results, attendance and wagering info: