The Team GB athlete announced she was withdrawing from this summer's games just four days before the opening ceremony.

Who is she, what is she accused of doing, and what has she said about it?

Who is Charlotte Dujardin?

The dressage rider has won six Olympic medals, making her Britain's joint-most decorated female Olympian.

Dressage is described by the Olympics as "the most advanced form of horse training, where horse and rider perform a series of artistic movements to music".

At the London 2012 Olympics, Dujardin won gold medals in the individual and team dressage, while in Rio in 2016, she took gold in the individual competition and silver in the team event.

Three years ago, at the postponed 2020 Tokyo Games, she claimed bronzes in both the team and individual competitions.

She had been set to compete in both the individual and team events in Paris.

What does the video show?

The video, which can be seen at the top of this article, shows Ms Jardin whipping a horse repeatedly.

The whistleblower's lawyer Stephan Wensing told Sky News the incident happened two and a half years ago at a private barn in the UK, where his client, who took the video, was watching a lesson as a sponsor.

Mr Wensing's client said they had seen similar abuse several times while working with Dujardin, but felt compelled to film because of how badly the animal was being treated.

The client said they hadn't reported it before now because they felt intimidated by her prestige and had been warned by people in the dressage community to stay quiet, but felt they had to act with the Olympics coming up.

Mr Wensing told The Telegraph that while giving a lesson to a student, Dujardin "took the long whip and she was beating the horse more than 24 times in one minute and really hard, really harsh, really tough".

He added it was like "an elephant in the circus".

The video, which was aired on Good Morning Britain on Wednesday, allegedly shows Dujardin walking beside the horse, which is carrying another rider, and whipping it along.

What has she said about the video?

Dujardin said the video shows her making "making an error of judgement during a coaching session".

She said what happened was "completely out of character" and "does not reflect how I train my horses or coach my pupils".

But she said "there is no excuse" and she was "deeply ashamed" and "sincerely sorry".

Dujardin said she will "withdraw from all competition - including the Paris Olympics - while this process takes place".

"[I] should have set a better example in that moment," she added.

She said she was "devastated that I have let everyone down, including Team GB, fans and sponsors".

Past disqualification due to 'blood on horse'

Ms Dujardin was disqualified from the European Championships in 2019 after blood was found on her horse.

She had been on course to take silver before she was eliminated after a routine check of the animal showed a "very small amount of blood on her side", British Dressage said at the time.

In a statement released by the organisation, she said: "I am obviously absolutely devastated - nothing like this has ever happened to me before.

"The health and welfare of my horses is always my number one priority, but of course I accept the decision."

World governing body investigating

The world governing body - the International Federation for Equestrian Sports (FEI) - has provisionally suspended Dujardin for six months, following an official complaint to the organisation.

The complaint outlined "allegations of animal welfare misconduct", which the FEI will now investigate.

British Equestrian (BEF) and British Dressage (BD) have also imposed provisional suspensions from all national and international competitions pending the outcome of the FEI investigation.

British Equestrian chief executive Jim Eyre said: "We do not condone any behaviour that goes against our guiding principles and take a zero-tolerance approach to any breach of our equine welfare policies.

"These historic allegations are deeply upsetting for everyone involved in our sport, but we fully support the FEI investigation and will take any appropriate disciplinary action when this process is complete."

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What are the rules about horse riders using whips?

The British Riding Clubs (BRC) rules on whips say a whip should only be used to support how the rider is directing the horse with their seat or legs.

"It must never be used to vent a rider's temper; any use for such a reason is automatically excessive," the rules say.

The whip is supposed to be used as a communication tool rather than a means of punishment.

The BEF code of conduct says "abuse of a horse" - including with a whip - "will not be tolerated".

The FEI has proposed tightening its rules on whips. The current rules state the whip should not be used more than three times in a row; the federation wants to reduce this to two.

It also wants to expand the "excessive use" definition to say "all other means of using the whip is considered excessive".

Riding since two-years-old

Dujardin took up riding when she was two-years-old and was 13 when she first tried her hand at dressage, according to the Olympics website.

She was born in north London in 1985 and brought up in Hertfordshire.

Hailing from a modest background, but competing in an expensive sport, she bought her first Grand Prix horse in 2007, thanks to money left to her by her late grandmother.

It was at that stage that she took up dressage competitively, having earlier aspired to be a jockey.