AN investigation is under way today into the deaths of two horses who collapsed and died after apparently being electrocuted in a freak accident at Newbury racecourse.

The meeting had to be abandoned after Fenix Two and Marching Song were killed as a result of what is believed to have been an electric shock from underneath the paddock.

A further two horses were seen to "wobble" and a lead rein on one of the dead animals was rumoured to have shown traces of burning.

Racing was cancelled after yesterday's first race due to health and safety concerns.

Newbury chairman Christopher Spence said: "It's a nightmare for everybody. We can't be certain what it is, we all think it's electric, but we don't know."

He added that the cause of the horses' deaths had not been established.

Last night, it was confirmed that electrical engineers called to the racecourse had discovered a cable under the parade ring.

A spokeswoman for Newbury racecourse said: 2The Southern Electric Board came in and did an investigation and found a cable.

"At this stage we cannot confirm if that definitely was the reason for the incident."

Newbury joint managing director Stephen Higgins said there was a "distinct possibility" that maintenance carried out before yesterday's meeting had disturbed the cable, which is believed to have been buried for at least 40 years.

"We have done some routine maintenance during the week, we do that every race meeting before racing, and whether or not that has disturbed something in the ground that had caused this catastrophic incident to occur to those horses we are not sure yet, but it is a distinct possibility."

Mr Higgins also suggested that the reason the horses, rather than the spectators, were affected was due to the animals' metal shoes and greater number of legs.

An inquiry and immediate post-mortem examinations for the horses was announced following the incident.

Jonjo O'Neill, trainer of Fenix Two, said he noticed the horse in front of his, Kid Cassidy, go down on his knees before his horse was struck.

''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,'' Mr O'Neill said.

Marching Song's part-owner Graham Thorner said the fallen horse had ''great potential''.

He added: ''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'.''

''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.''

Asked about rumours that a lead rein on one of the dead horses looked burned as if it had been shocked, stipendiary steward Paul Barton said: ''One of the reasons we couldn't continue was because of all the speculation.

''The lead rein could have snapped if it was stood on by another horse when it was on the ground.

''The rein will go away for forensic examination to establish what happened to it.''

Racegoers will be given a 100 per cent refund.

Professor Tim Morris, director of Equine Science and Welfare for the British Horseracing Authority, confirmed a full investigation is under way.

He said yesterday: ''Following the tragic events at Newbury, our sympathies go out to connections of the two horses that died, Fenix Two and Marching Song.

''We have launched a full investigation into the events before the first race. Whilst there are suspicions that an electrical fault was the cause and this is being looked into by the racecourse and relevant authorities, it is important that we investigate other possible causes.

''Both horses have been sent for post-mortem examinations, and samples from both horses, and from the other two horses involved in the incident, have been taken and will be analysed.

''We will also be testing a sample of the water supply and have secured and will review all of the CCTV footage from the racecourse stables and footage from the parade ring itself at the time.

''We have gathered evidence and statements at the racecourse from the connections involved with the incident, including trainers, jockeys, stable staff and owners, the racecourse and BHA veterinary officers, and the racecourse executive including the health and safety officer.''