Royal Wedding is, fittingly, a son of the sire, King's Best, and won at Fontwell in February.

He is owned by former Marks & Spencer director Don Trangmar, who is due to be in attendance on the gelding's big day.

Ladbrokes spokesman David Williams said: "Royal Wedding could set alarm bells ringing as the nation switches its attention from the Abbey to Fontwell.

"The country will be in a celebratory mood, but the bookies won't be smiling if Royal Wedding scores at the races.

"It could easily be the best-backed horse we've seen in ages and could land us with a multi-million pound headache."

Paddy Power, of the Irish bookmakers of the same name, added: "Regular racing fans may not back Royal Wedding just because of its name, but any casual racegoers at the track are sure to support him.

"This, combined with the publicity of the horse running that will attract loads of money online and in our shops, will make this a huge people's gamble that we fear on a very special day."

Gifford, however, insists Royal Wedding's participation at Fontwell is purely coincidental.

"This race slotted into his schedule," said the Findon-based handler.

"He was not left in the race on purpose because of the royal wedding.

"He's a winner at Fontwell, after all, and will love the fast ground.

"His owner will be there and I'd like to think he has a good chance."

Royal Wedding will be ridden by Liam Treadwell, who won the John Smith's Grand National in 2009 aboard 100-1 shot Mon Mome.

He finished fourth to Commemoration Day at Stratford on his most recent start at the beginning of the month, and is poised to be sent off a warm market-leader on Friday.

Coral spokesman David Stevens added: "We predict that Royal Wedding will be priced at approximately 7-2 on Friday morning, but the sheer volume of bets placed could see those odds shorten dramatically, and he is likely to start hot favourite for the race.

"Not since Party Politics won the Grand National, just five days before the 1992 General Election, has a horse with a more appropriate name been in action."

Phil Bell, Fontwell Park general manager, welcomed the return of Royal Wedding to the West Sussex circuit.

He said: "We are delighted the owners have decided to run the horse on our Royal Wedding Race Night.

"It will provide national publicity for both Fontwell Park and horseracing in general.

"We hope Royal Wedding can register a very topical victory at the track."