Bookmakers are forecasting record levels of turnover at this week's Cheltenham Festival.With 27 races over four days, the betting industry is braced for the biggest week of the year with over STG300 million ($A447.56 million) set to be gambled.And with races lasting an average of barely over five minutes each, a staggering STG35,000 ($A52,215) a second is set to smash bookmaking records, according to Ladbrokes."Economists who tell us we're in a financial slump have clearly never been to Cheltenh

Bookmakers are forecasting record levels of turnover at this week's Cheltenham Festival.

With 27 races over four days, the betting industry is braced for the biggest week of the year with over STG300 million ($A447.56 million) set to be gambled.

And with races lasting an average of barely over five minutes each, a staggering STG35,000 ($A52,215) a second is set to smash bookmaking records, according to Ladbrokes.

"Economists who tell us we're in a financial slump have clearly never been to Cheltenham in March," spokesman David Williams said.

"The Festival gets bigger each year and the massive sums of money that swill around on-course and online and in shops up and down the land make us go weak at the knees.

"We've only just removed the bandages from last year. It was horrific as all the fancied runners seemed to score. We're desperate for a change of luck."

William Hill fear a payout in excess of STG6 million if well-known names of Hurricane Fly, Sizing Europe, Big Buck's and Long Run all win the four Championship races again - a feat which has never happened before.

"Cheltenham is the most hotly-anticipated week of racing in the entire year, and the equivalent of Christmas to many grown men!" a spokeswoman for William Hill said.

"The bookies' annual battle with the punters begins in 48 hours but the perfect storm is already brewing against us."

Gold Cup day on Friday could mean upwards of STG40 million gambled on one race alone with Long Run and Kauto Star set to renew their rivalry.

"At the moment we're fearful of Long Run but Kauto Star has an enormous following. If neither of them win bookies will be in rapture," Williams said.