Accidental electrocution was to blame for the deaths of two horses in the paddock at Newbury last Saturday, an investigation has found.
The Berkshire track has been officially cleared by the British Horseracing Authority to hold the rescheduled totesport Trophy Hurdle meeting tomorrow after the meeting was abandoned following the first race at the weekend.
Two horses, Fenix Two and Marching Song, were about to be mounted by their jockeys on the grass in the parade ring when they suddenly collapsed.
The decision from the BHA follows the receipt of post-mortem examination reports and the results of sampling and information from the racecourse and Southern Electric Power Distribution.
Newbury have assured the BHA the parade ring area is now safe for use by horses and humans and that a cable previously located within the parade ring area has been removed and disconnected.
Southern Electric has also confirmed it is satisfied electricity cables within the racecourse are operating normally and within required safety standards at the time of testing.
Professor Tim Morris, director of equine science and welfare for the BHA, said: "The authority has been officially informed that there was leakage of electricity from a cable under the parade ring in the area where the incident occurred.
"There was immediate veterinary attention, and our inquiry on the day noted the racecourse veterinary surgeons felt a tingling sensation when examining the horses, and that the veterinary surgeons noted particular clinical signs such as muscle contractions.
"Both horses that died, Marching Song and Fenix Two, have undergone post-mortem examinations which showed sudden cardiac arrest as the cause of death.
"Samples taken from the horses affected have shown no evidence of substances that could have caused this incident.
"These findings are all consistent with the cause of death being accidental electrocution and at this stage we are not investigating any other cause of death.
"I can also confirm that, contrary to speculation, no evidence of any burn marks around the mouth was found on post-mortem examination, neither were such marks found by the veterinary surgeons on the horses at the start."
The BHA will continue further investigations to ensure they learn as much as possible from the incident and their conclusions will be published at a later date.
Newbury's joint managing director Stephen Higgins said: "The post-mortem results indicate accidental electrocution as the cause of death of the two horses, within the parade ring area.
"The investigation by Southern Electric Power Distribution continues, to establish the cause of the electrical leakage.
"I would like to stress again that Southern Electric has confirmed that there was no danger to the public on Saturday.
"Further to the BHA's statement, we are pleased that racing has been authorised for Friday.
"Once again we would like to extend our condolences to the connections of those horses and will continue to liaise with those affected."
The Merry Giant was a third of four horses to have been affected in the parade ring and ran badly when taking part in the race.
But trainer Rebecca Curtis said today: "He seems absolutely fine now."