In a statement released by the British Equestrian Federation, Dujardin 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."

Dujardin is eliminated from the whole championship, meaning she cannot contest individual medals in Thursday's grand prix special, which is also a qualifier for the showpiece individual freestyle on Saturday.

Equestrian sport's world governing body the Federation Equestre Internatonale said: "Blood was found on the left flank of the horse in the post-competition check. In accordance with article 430.7.6.2 of the FEI dressage rules, this results in elimination.

"Elimination under this rule does not imply there was any intent to injure the horse, but the rules are in place to protect the welfare of all competing horses."

It meant that Dujardin, who won Olympic gold in London and Rio, had her score erased from the team event and Britain's overall total dropped by almost eight points.

The combined efforts of Carl Hester, Gareth Hughes and Charlotte Fry – Hester and Hughes scored grand prix personal bests – left Britain on 228.991, which was only enough for fourth.

The British Equestrian Federation said it would not be appealing against the decision, and described it as "fair."

In a statement, the BEF said: "Following their test, a routine post-test inspection by the FEI stewards revealed a small trace of blood on the flank of Mount St John Freestyle, the ride of Charlotte Dujardin.

"As is the FEI rules, any blood found during this inspection results in elimination.

"Having consulted with our dressage team veterinarian Andre Buthe, who also inspected the horse, we feel this decision is fair in respect that the welfare of our horses and riders is absolutely paramount. We will not be appealing their decision."

Great Britain's chef de mission Vikki Underwood added: "This is extremely difficult because in Britain we pride ourselves on our animal welfare.

"Charlotte is one of our most respected and talented athletes, who dearly loves her horses, but she would not hesitate to accept this decision.

"It takes a great deal of teamwork to get the horses and riders to a championship, and all the connections will be devastated, but the horse is fit and well and will contest many more championships."

Dujardin is one of the biggest names in equestrian sport, having won successive Olympic titles, plus World and European crowns on her previous horse Valegro, which was retired after the Rio Olympics three years ago.

The combination also set new world records in grand prix, grand prix special and freestyle disciplines that still stand.

Germany, led by multiple major championship medallist Isabell Werth, emphatically defended their European title, with Holland climbing to second and Sweden third following Dujardin's elimination.

Britain had secured Olympic qualification before Rotterdam, but Ireland booked one of the remaining Tokyo tickets on offer – a first for Irish dressage – when Judy Reynolds, Kate Dwyer, Anna Merveldt and Heike Holstein finished seventh.