Known as the "greatest show on turf," the U.K.'s Cheltenham Festival of horseracing kicked off earlier this week with £3.825 million ($6.4 million) up for grabs in prize money.
Being the most famous jump-racing competition in the world, and one of the biggest horse festivals of the year, Cheltenham offers more in prize money than any other jump competition and is big business for bookmakers, with nearly 250,000 punters expected to attend this year's meeting.
The event is worth about £350 million pounds to the horse-racing and betting industies and is overshadowed only by the Grand National in terms of betting volumes, according to Irish gambling firm Paddy Power.
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"Punters place 5000 bets per minute on our website during the festival. It is absolutely relentless," said a Paddy Power spokesperson.
The Gold Cup event, due to take place on Friday, is the highlight of Cheltenham Festival and the most prestigious jumps race in the British racing calendar. It is set to make-or-break bookmakers, said Paddy Power, with the main race offering £550,000 in prize money. Bookmakers dubbed last year's Gold Cup day "Black Friday" because of the hefty pay-outs to betters.
"Bookies came out on top on the first day (of this year's festival), but it has evened out since, punters have gained some ground. Last year it was a blood bath for the bookies with so many favorites winning. The Gold Cup will be make or break," said Paddy Power.
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Andy MacKenzie of sports and financial-betting firm Spreadex, said the stakes were incredibly high for bookies.
"It is probably not as much as the Grand National, in terms of one race being the biggest for betting. On the meets, hundreds of millions of pounds are being staked, and in terms of liabilities you are going into billions in terms of liabilities for bookmakers," said MacKenzie.
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"It is known as the 'World Cup of horseracing, the 'greatest show on turf' – so for bookmakers, these four days are massive when it comes to horse racing," he added.
—By CNBC's Jenny Cosgrave: Follow her on Twitter @jenny_cosgrave