Police said a substantial reward is being offered following the theft in Westmancote, Worcs, on Thursday.

The money - £27,431 in cash and 9,213 euros - was stolen when Keith Harris, from Warrington, and his colleagues went out for a meal.

Mr Harris said he was "clearly targeted" as the five surrounding bungalows were not broken into.

Be vigilant

It coincided with the theft from another bookmaker at the festival.

Masked raiders stole thousands of pounds from Freddie Williams after they stopped his Jaguar car at Fossebridge, Gloucs.

Mr Harris, who works for Liverpool-based Pat Whelan Racing, said: "Cheltenham Festival is the largest National Hunt meeting on the racing calendar so you have to have a substantial amount of cash with you - considerably more than you would at any other event."

West Mercia Police are warning bookmakers and racing fans staying in the area for the festival to be extremely vigilant about securing their money.

"While not necessarily practicable, we advise bookmakers and visitors to deposit substantial amounts of cash in a bank overnight and retrieve it the following day," a spokesman said.

"This would help to minimise opportunities for ever-alert criminals."

Mr Harris said the reward was being offered for information leading to the return of the money and the conviction of offenders.