The 66-year-old, one of New Zealand's most celebrated Olympians, was handed an interim suspension by the British Horseracing Authority (BHA) after footage emerged of him viciously beating a horse with a branch.

"This interim suspension means that while investigations continue into the circumstances of this incident, Sir Mark will be unable to race horses in Great Britain or internationally," the BHA said.

"The trainer has admitted the individual involved in the video was him, has apologised for his actions and agreed to the imposition of an interim suspension."

The video, widely shared on TikTok, showed Sir Mark whipping a horse multiple times on its hindquarters while trying to get it to the water jump during a cross-country clinic in Scotland.

On Thursday (April 14), the BHA issued the following statement after the independent disciplinary panel imposed a suspension of four months. 

"We are grateful to the disciplinary panel for their time in considering this case and acknowledge the penalty handed down this afternoon," the BHA said. 

"As Sir Mark has himself recognised in public statements since the video emerged and in accepting that he was in breach of Rule (J)19, his behaviour on this occasion fell short of the standard expected of all licensed individuals and ran contrary to the values of care and respect for the horse that underpin British racing."

The former athlete, who won individual gold medals at the Los Angeles 1984 and Seoul 1988 Olympic Games, had served two months of the ban while the other two months were deferred. 

His success in the sport led to him receiving a knighthood in 2013 from Prince Charles.

Judge Brian Barker, chair of the independent panel, said that the BHA and Sir Mark's legal team reached a "common ground" for his punishment.

After analysing the footage of the incident, Barker said that both parties agreed that the horse showed no "sign of fear or distress at any time" and that the well-being of the horse did not appear to have been "compromised". 

Barker further mentioned that Sir Mark was "calm in his attempt to encourage the horse to drop into the water, having first satisfied himself that the horse was capable of doing so", while adding that the use of a "light branch" instead of a BHA approved "manufactured whip" was not appropriate. 

"Those who are more likely to be in the public eye must expect a greater level of scrutiny by the public," Barker said.

Although the whip can be used in British racing for the purpose of correction, there are strict limits on the amount of times it can be used. 

Riders and animal welfare campaigners from all over the world have been condemning Sir Mark. 

Under British racing regulations, once the whip is used, the horse must be given a chance to respond.

The two-time Olympic gold medallist apologised for the incident and stepped down from his role as World Horse Welfare patron. 

"One of the main things I preach is about establishing a mutual respect between horse and rider and that patience and kindness is the best way to get results," he said.

"I believe this is one of the main attributes along with a great empathy with animals that has enabled me to have a long and successful career in eventing."

Sir Mark added: "I am very disappointed in myself that I did not adhere to that in this case."

The International Equestrian Federation, British Eventing, the British Horse Society and Equestrian Sports New Zealand have all condemned Sir Mark's actions.