Roger-Yves Bost hailed his Hickstead triumph as the greatest of his career after becoming the first Frenchman in 59 years to win the King George V Gold Cup.

The 35-year-old won the top prize for male riders at the Royal International Horse show on Ideal de la Loge after a faultless round in a six-horse jump-off.

German Heindrich Engemann was second and Britain's William Funnell followed up his Hickstead derby win last month with a third-placed finish.

Bost has won a string of grand prix competitions, been a World Championship winner with his country and has competed in the Olympic games.

But he says winning the prestigious 99-year-old competition tops the lot.

He said: "This is the biggest win for me. It was a very difficult course but it was my day.

"I first came here in 1985 so it is good to have won it at last."

Bost is hoping his triumph will be enough to see him selected for the five-man French team for the World Championships later next month.

He added: "I don't know if I'm included yet, hopefully, after this I will be."

Three-time winner John Whitaker finished sixth in the jump-off in what was largely a disappointing day for Britain's top male riders.

Ben Maher, who was one of the big hopes, finished 11th with four faults, John's brother, Michael Whitaker, downed two fences on Insul Tech Portofino 63 in the first round and finished 20th and Nick Skelton was eliminated after being thrown off Arko II at the fifth jump.

Skelton has now ruled himself out of going to the World Championships with his usually reliable ride.

He said: "I don't know what happened at the fence but after what happened, I can't take the risk."

The Queen Elizabeth II Cup, the top competition for female riders, was won for the second time by American Molly Ashe.

The 2004 champion came out top in a five-horse jump-off on Lutopia, beating Britain's Jane Annett into second place.

Both riders were faultless but Ashe edged it with a faster time.

It was the second time Annett had to settle for the runners-up spot, having finished second in 1997.

Ashe, 35, said: "It was a lot tougher than when I won it the last time and I was lucky that I was riding a once in a lifetime horse."

Annett, who was back in the saddle after breaking an ankle in the derby, knew her time on Cullawn Diamond was never going to be good enough.

She said: "I thought it could be beaten. He is a good jumper but he is not very good against the clock."