Describing himself as "very disappointed" at the decision, he has criticised the "lack of consultation and communication" by the International Modern Pentathlon Union (UIPM) over the issue, while placing ultimate responsibility on the International Olympic Committee (IOC),

Following the UIPM’s confirmation on Thursday (November 4) that its Executive Board had passed a motion to remove riding from the sport in the wake of the controversy over the equestrian element at the Tokyo 2020 Olympics, Choong was among numerous athletes to express outrage at the decision on social media.

"Let’s stop the UIPM destroying our sport," Choong tweeted.

"They must not be allowed to remove the riding element of modern pentathlon without discussing it with us athletes and its member nations!”

Armstrong was referring to comments made individually by athletes on social media and speaking before the announcement by a group of 667 leading past and present athletes calling for UIPM President Klaus Schormann and the entire Executive Board to resign following a decision they described as having "undermined 109 years of modern pentathlon."

The signatories included Choong and Britain's women's Olympic champion Kate French, as well as the Czech Republic's London 2012 gold medallist David Svoboda, and Britain’s Sydney 2000 bronze medallist Kate Allenby.

Speaking to insidethegames, Armstrong said: "From my point of view what I don’t want to do is to try to muzzle the views of the athletes.

"They have got to freely express their opinion.

"The reason why the UIPM have imposed this at such short notice is because of direction from the IOC, and that direction also came with a timetable, in that they wanted a decision from us on riding by November 18.

"Which is not exactly very accommodating.

"And Joe is absolutely right to be fair on it - in terms of making a change like that without consulting with the athletes in the sport, it does feel uncomfortable.

"It feels uncomfortable that we weren’t consulted as well.

"It’s been something that has been talked about for some period of time.

"But for it to happen like this at such short notice - I am the chairman of the British federation which has been probably the most successful in recent times if not the largest - and the first I heard of it was on Monday of this week.

"That’s what I find particularly difficult to cope with - the lack of consultation and communication.

"But I think that’s caused by the IOC moving very quickly."

Armstrong, formerly chief executive of Premiership Rugby club Wasps, was a director of the 2017 World Athletics Championships in London and was appointed to his position at Pentathlon GB in 2018.

In 2019 he became chief executive of the Racecourse Association, one of the three bodies running British Horse Racing.

"I am very disappointed that riding has been taken out," he added.

"Essentially it has been the same five disciplines since 1912.

"So for that change is a sad day for the sport and I think it is unfortunate that the IOC have imposed this on the UIPM."

In a statement issued this afternoon the UIPM said it was "fully aware" of the concerns voiced by current and former athletes.

"All athletes are invited to participate in an open dialogue on this matter so that they can better understand the background," said the governing body.

"The open dialogue will be scheduled within the next week.

"All opinions and ideas are welcome and will be fully taken on board for the fifth discipline discussion according to the announced criteria.

"As part of UIPM's normal democratic process, an electoral UIPM Congress will take place in three weeks on November 27 and 28, where member federations will have the opportunity to discuss and debate all motions on the agenda.

"All athletes are encouraged to consult and talk to their National Federations about any concerns or proposals.

"UIPM is committed to working with our current and future athletes to help them to realise their dreams in the future Olympic Games."

Several horses refused to jump for riders at this summer’s Tokyo 2020 Olympics, including Saint-Boy, ridden by Germany’s Annika Schleu, who was leading the competition entering the riding event.

German coach Kim Raisner was later sent home following video footage showing her punching Saint-Boy, while Schleu was criticised for repeatedly whipping the distressed horse.