Wetherby racecourse is to be investigated by the British Horseracing Authority (BHA) after four horses died during the track’s opening day of the jumps season on Wednesday (14 October).

The RSPCA has called on the BHA to conduct an enquiry after the incidents, which marred the start of the winter season for the track.

Paul Struthers, media relations manager for the BHA said: “Wetherby had received positive reports about the ground ahead of the meeting and we are not aware of any complaints made about the ground on the day.

“It is always desperately sad when a horse has to be put down as a result of injuries sustained during racing. In circumstances such as these it is our policy to undertake a thorough review and look into all of the circumstances – the course, the horses, the injuries and any other relevant information — to establish whether common factors are involved.

“We have already requested reports from our racecourse inspectorate, veterinary team and stewards, who were all in attendance yesterday. We will await receipt of the reports and our other findings and will then liaise closely with the racecourse, trainers, jockeys and the RSPCA.”

Two horses died in the Bobby Renton Chase — the feature race of the day. Divex, trained by Micky Hammond and Marrel — who fractured a hind pastern in a fall.

Later that day Nut Hand, trained by Tim Easterby was put down after pulling up lame in a maiden hurdle and the Patrick Haslam-trained Miss Gibboa broke a leg.

The ground was officially good to firm.

The course has undergone £50,000 of improvement in the past few months after ground and conditions were criticised last season.

The course has faced criticism since it parts of it were re-laid in 2007 to make way for the widening of the nearby A1.

David Muir, the RSPCA’s equine consultant said: “There is no justification for the unacceptable number of deaths and injuries that occurred to racehorses on this sad day of racing.

“As standard procedure, I walk and check a course and obstacles prior to a day’s racing when visiting such events. On completion of this task, I could not identify any particular element in the course preparation that should have rung alarm bells to prevent racing.

“This decision was backed by BHA inspectors, regional course inspectors and several trainers.

“Parts of the course have been changed and there is an element of inconsistency in some areas. Some sections may well need to be improved if evidence shows this was a contributory factor to yesterday’s incidents.

“The only real test of a course is to race on it and on this day Wetherby racecourse simply failed.”