Seven jockeys have been suspended in a dramatic conclusion to the London National withe the race declared void.

A field of 14 runners went to post for the three-mile-five-furlong handicap chase - and the drama began after Houblon Des Obeaux slipped on the bend after jumping the Pond fence for the first time.

The rest of the runners raced on up the home straight and headed out for the second circuit.

Approaching the Pond fence for a second time, a member of the ground staff displayed a yellow flag, which is shown to indicate to riders that there is a serious incident ahead and that jockeys must stop riding and the race declared void.

But rather than pulling up, horses bypassed the obstacle and subsequently the stricken Houblon Des Obeaux behind the screens, with jockeys continuing to ride out the finish and negotiating the final two obstacles.

The Neil Mulholland-trained Doing Fine (14-1) passed the post in front in the hands of 7lb claimer Philip Donovan, but a stewards' inquiry was immediately called and following lengthy deliberations the race was declared void.

It was also confirmed that Houblon Des Obeaux had suffered a fatal injury.

As well as Donovan, the riders suspended by the stewards were Jamie Moore, Daryl Jacob, Harry Skelton, James Davies, Stan Sheppard and Adam Wedge, who earlier in the day had ridden his first Grade One winner, courtesy of Esprit Du Large.

"The yellow stop-race flag was put in place because there was a stricken horse on the bend, just coming into the home straight," Chris Rutter, the chief steward at Sandown, told Racing TV.

"When there is a yellow stop-race flag, the race has to be declared void.

"There were seven jockeys who continued in the race. The stop-race flag was just to the left of them and they appear to have bypassed it and bypassed the Pond fence and just carried on up the home straight.

"For that reason, all the jockeys who continued in the race were given a 10-day suspension because they failed to stop when they should have stopped.

"There's some confusion - they (the jockeys) said they didn't (see the flag), but the film clearly shows that the flag was there and that some of the jockeys have gone to stop and then started riding again."

The jockeys said they were all likely to appeal.