The historic race was the first to be run in Britain under written rules after it was instituted by an Act of Parliament in 1665 by King Charles II.

Originally it was stipulated that the race should always be run on the second Thursday in October and that no “serving men or grooms” were allowed to take part. It was later moved to a weekend spot in a bid to get more spectators.

The three-mile, six-furlong flat race is restricted to amateur riders who are not licensed by the Jockey Club

Among this year’s competitors will be 58-year-old Jean-Luc Guillambert, father to jockey J P and Racing Welfare fundraising executive Francoise, who has shed four stone to take part.

He has prepared for the race by cycling to trainer Vince Smith’s Exning yard each morning from his Newmarket home before riding out his two lots, not having ridden for over 26 years.

In January he tipped the scales at more than 17 stone but on Saturday plans to weigh in at around 12½ stone.

He is hoping to place a charity bet on himself with any winnings being donated to Racing Welfare. Interested bookmakers should contact Mr Guillambert on 07774 272650 or Francoise at Racing Welfare on 01638 565242.

The first prize for the successful rider is the Golding Perpetual Challenge Plate, a £125 Golding voucher and a memento presented by Powters. There are Golding vouchers for the second, third and fourth-placed riders, while each of the first four will receive a box of celebrated Powters Newmarket sausages.

Newmarket Racecourses’ Director of Racing Michael Prosser said: “I feel the contest is a fitting annual tribute to both those that established horseracing in the 17th century and Newmarket’s heritage. It is such an historic event, underlined by the fact that on Saturday the 339th chapter will be written.

“The staging of the race is an appropriate way to bring down the curtain on summer racing at the July Course. This is the third year we have held it after the final card of the year at the track and it has worked exceptionally well since it was switched to its current slot.

“There will be a terrific atmosphere with a large crowd enjoying a terrific spectacle.”