Charlotte Dujardin’s mentor and teammate Carl Hester has signed a letter “universally condemning” her for abusing her horse and supporting the decision to suspend her for six months.

Hester, who will compete in his seventh Olympics in Paris next week, was one of 10 board members of the International Dressage Riders Club to sign the letter after a video was released of Dujardin whipping a horse 24 times in a minute.

“The Board Members of the International Dressage Riders Club (IDRC) universally condemn the actions of Charlotte Dujardin as seen in the video footage made public by Stephan Wensing from European Equine Lawyers on behalf of his client,” the letter states.

“The Board members are resolute that equine welfare must always be placed uppermost and at all times,” the letter adds.

The fact that Hester has co-signed the ­letter is especially significant given he not only helped Dujardin in the early stages of her career, but she trains in his yard. The 57-year-old Hester also bought Dujardin’s horse, Valegro, for £4,000 which she then rode to win gold at London 2012 and Rio in 2016.

The letter adds that riders should promote “only ethical training methods and practices” – and it encourages them to abide by the International Equestrian Federation Code of Conduct for the Welfare of the Horse together with all International Federation for Equestrian Sports (FEI) regulations which support and protect equine welfare standards in and out of competition.

“The IDRC Board supports the actions taken by the FEI, the British Equestrian Federation and British Dressage to provisionally suspend Ms Dujardin,” it adds. “It notes that Ms Dujardin has stated she has no excuse for her actions and has also expressed her shame and regret.”

Dujardin now finds her career in tatters after being kicked out of the Olympics and suspended for six months. To compound her problems, UK Sport has also suspended her lottery funding after the video of her hitting the horse became public.

In a statement released on Tuesday, Dujardin admitted that there is “no excuse” for her behaviour and that she was “deeply ashamed” of the error of judgment.

“What happened was completely out of character and does not reflect how I train my horses or coach my pupils, however there is no excuse,” she said. “I am deeply ashamed and should have set a better example in that moment.”