In a letter written to Schormann, seen by insidethegames, Schmitt, who is a former IOC Presidential candidate, ex-President of Hungary and has been an IOC member since 1983, criticised the decision and the manner in which it was taken.

At a secret UIPM Executive Board meeting earlier this month, members exercised a force majeure clause to enable the body to represent the General Assembly and amend competition rules.

Schmitt says Schormann and the Executive Board do not have this power, writing: "In order to take horse riding out from the programme, you need to change your Fundamental Rules (Deed of Foundation), which cannot be done by simple decision of the Executive Board of the UIPM.

"To change the basic rule you need a two-thirds majority of your General Assembly."

The objection was also made by the Modern Pentathlon Association of Denmark (MPADK), which argues the UIPM Executive Board’s decision is in breach of the organisation’s statutes and competition rules, which the MPADK says makes it clear that horse riding is "integral to the sport of modern pentathlon".

It is claimed statute amendments would be required for the discipline to be changed, with the MPADK arguing "only the General Assembly has the power to amend the statutes" as the organisation’s supreme legislative body.

The UIPM's decision stemmed from a disastrous riding competition at the Tokyo 2020 Olympics, where German coach Kim Raisner was sent home after punching the horse Saint-Boy, who had refused to jump for Germany's Annika Schleu, the competition leader at the time.

The UIPM has said the IOC, which is expected to ratify the Olympic programme for Los Angeles 2028 next year, implied modern pentathlon will not be a part of the Los Angeles Games with riding as one of its five disciplines. 

Schmitt, however, directly refutes this claim, saying: "As an IOC member for 39 years, I can assure you that the IOC has never asked you to change the programme, the timing, the composition or the rules of modern pentathlon."

Schmitt later writes: "The IOC never asked you and your federation to drop horse riding from the programme", adding that Los Angeles signed the hosting contract with modern pentathlon and riding included.

Schmitt's letter follows a series of public criticisms of Schormann and the UIPM.

Almost 700 modern pentathletes called on Schormann and the Executive Board to resign following the decision, which they described as having "undermined 109 years of modern pentathlon".

Several National Federations also hit out at the UIPM, including Pentathlon Canada, the Modern Pentathlon Federation of Sweden, the Finnish Fencing and Pentathlon Federation and representatives from Poland, the Czech Republic, Kyrgyzstan and Hungary.

Schmitt's letter follows the "open dialogue" session with athlete representatives that the UIPM promised as a replacement discipline is decided upon.

The invite-only meeting was held on Friday (November 12), and athletes on the call have criticised the lack of transparency.

Held over Zoom, with those who wished to attend having to express their interest in doing so beforehand, the meeting was carefully managed by the UIPM.

Athletes were muted for the entirety of the session, bar when they were allowed to ask a question.

They had to submit these questions in advance and were muted by UIPM general secretary Shiny Fang "the minute you finished delivering your question", a source said.

This meant any query or discussion was not possible, with UIPM Executive Board members taking turns to share their general opinions about the matter, avoiding the questions and eating up the allotted two-hour time period.

London 2012 silver medallist Samantha Murray said the UIPM made every effort to keep discussions closed.

"The UIPM has made their decision," Murray told insidethegames.

"Absolutely.

"It was so apparent.

"They have 100 per cent made their decision.

"They just did not entertain the topic of 'how could we solve equestrian?'"

Murray added: "It was joining a conversation with individuals who are so vain and self-absorbed that they just want to hear their own voice for eight to 10 minutes, rather than actually embrace a discussion and understand other people's points of view and ideas and try to learn and adapt."

The UIPM Congress is due to take place on November 27 and 28, where "member federations will have the opportunity to discuss and debate all motions on the agenda," the UIPM claimed.