Racing was united in shock and sympathy on Friday evening following the announcement that Stephen Yarborough, a stalls handler who had been airlifted to hospital from Haydock Park following an incident earlier in the day, had died as a result of his injuries.

Yarborough is believed to have been run over while the stalls were being moved before the day’s fourth race.

A statement by RaceTech, the company which employs stalls handlers at British racecourses, said: “Our dear friend and colleague Stephen Yarborough sadly passed away following serious injuries incurred in his role of team leader of the starting stalls at Haydock Park racecourse.”

John Bozza, the chief executive of RaceTech, said that “our thoughts are very much with Stephen’s family, close friends and his colleagues at this very sad time.  Stephen was an experienced and popular member of the team; he will be hugely missed by everyone. We are doing all we can to support Stephen’s family and the investigation at this stage.”

Nick Rust, the chief executive of the British Horseracing Authority, said on Friday evening that racing has “lost one of our own”.

He added : “This is a tragic incident and we are all shocked and saddened. Stalls handlers carry out a brave and important job each day looking after the safety of the horses and riders and we are grateful for their work.

“British racing will come together in grief at this incident. We are one family and today we have lost one of our own. Our condolences and sympathies are with Stephen’s family and friends.”

Racing at Haydock was abandoned following the incident, which occurred as the runners were starting to enter the paddock before the fourth race.

Jason Fildes, Haydock Park’s general manager, said: “This is the worst possible news. I’m very upset for Stephen’s family and friends and there is a now a real sadness among the whole team. We saw Stephen regularly in his role working for RaceTech. It’s so tragic that this happened.”

The circumstances are being investigated by Merseyside police, who said in a statement: “Emergency services were called at around 3.40pm to reports that a starting stall coupled up to a tractor had been in collision with a male employee on the racecourse.

“The man, who was aged in his 50s, was pronounced dead at the scene. Next of kin have been informed.