Racing:Racing at Newbury was abandoned in extraordinary circumstances after Fenix Two and Marching Song collapsed and died in the parade ring before the first race.
An inquiry and immediate post-mortems were announced, with the reasons for the deaths unknown amid speculation the horses died from some form of electric shock emanating from underneath the paddock.
Some horses had already made it down to the start and there were reports that others had "wobbled" on entering the paddock.
Nicky Henderson was quick to withdraw his runner Kid Cassidy, while Andy Turnell, trainer of Marching Song, said: "It looks like they've been electrocuted. My fellow seemed perfectly all right and I was about to leg him up but he just went straight down."
Jonjo O'Neill, trainer of Fenix Two, said: "Kid Cassidy was in front and he took a turn. We thought he was bucking and kicking and he went down on his knees then he seemed to be okay.
"Mine reared up and we couldn't get him back, it was like he was stuck to the ground. It was the weirdest thing I've ever seen in my life."
Denman's owner Paul Barber was in the paddock and said: "The girl of Turnell's said she felt a tingling as she led them round and then Nicky's horse went down.
"They were getting the shocks off the grass, not off the tarmac. I've never seen anything quite like that ever."
Stipendiary steward Paul Barton said: "We are going to hold an inquiry and interview those connected with the horses. We are not going to use the parade ring for the rest of the meeting. The horses will parade in the pre-parade ring and leave from that point.
"The veterinary team are in charge of whatever precautions as far as the other horses are concerned. They have checked all other horses in this race."
Marching Song's part-owner Graham Thorner said: "I was very fond of him and he had great potential.
"To a layman with no evidence, you would say it was electrical. The lad who was with him was saying 'I'm getting an electric shock off this horse'. As a layman you would say that is what happened. The horses were kicking out at something and it seemed to be in an area leaving the paddock.
"It can't be coincidence four horses have done the same thing and two have died, all in the same area. Three people said they were getting a shock off the horse. I hope we find out what it was but it doesn't bring the horses back."
Henderson said: "About a minute before it happened, Kid Cassidy was walking in the same corner of the paddock. I had my back turned but my daughter said 'your horse has gone down'.
"He got back up again and he went to the start. All the horses at the start had their hearts checked and he was fine, but he was desperately keen so I decided to take him out.
"Electrocution is the most obvious possibility. Nobody is to blame really, but I think you'd only really find out when they've done a post-mortem. The worse thing is what happened to the horses and it's all very odd."
Despite running the first race, a decision was taking to call the rest of the big meeting off.
A statement released at 2.10pm read: "The Newbury executive have decided that racing today has been abandoned."