Charlotte Dujardin will defend her Olympic dressage gold on relative newcomer Gio, rather than Valegro’s immediate successor, Mount St John Freestyle. Dujardin made the decision after assessing which of her top-string horses would cope best with the heat and humidity expected in Tokyo.

Gio came out in Grand Prix last year and goes to the Olympic Games with even less competition experience than Valegro had in 2012, although Dujardin is confident Gio will deliver.

The chestnut 10-year-old was spotted by Dujardin during a clinic in the US in 2016. He has been seen infrequently in the arena while progressing through the levels. He performed his first FEI Grand Prix Special at Wellington, Hampshire, a late-arranged show in May, scoring 81.43%. On Wednesday, Gio appeared unfazed by 1,000 spectators at Royal Windsor Horse Show, where Britain’s Olympic dressage and eventing riders took part in an open training session.

Dujardin said, “After close consultation with the selectors, I will be partnering with Gio. The decision is no reflection on the incredible Freestyle, with whom I have also had great results throughout the year. She is a world-class mare, but we feel Gio is the horse for the team, for these Games.”

The other named dressage riders are Carl Hester (En Vogue) and Netherlands-based Charlotte “Lottie” Fry (Everdale) – the daughter of former British team member Laura Fry who died at the age of 45 in 2012 after a battle with cancer. Travelling reserve is Gareth Hughes (Sintano Van Hof Olympia.)

This is a sixth Olympic Games for Hester, also the trainer of Dujardin and Hughes. He said, “Undoubtedly this will be a very different Olympics, but to represent my country on the biggest stage is such a privilege for me.”

Britain’s eventing squad contains three of the world’s top-five ranked riders. All of them, including world number one Oliver Townend (Ballaghmor Class), are riding on the British Olympic team for the first time. Team-mates are Tom McEwen (Toledo de Kerser) and Laura Collett (London 52) with Piggy March (Brookfield Innocent) the alternate rider. Under the new format, March can be substituted at various stages should any of the initial trio get into difficulty.

Britain was due to announce all three of its teams at a joint occasion earlier this week but this had to be delayed, reportedly because of a legal difficulty over the naming of the jumping team. British Equestrian says the jumpers will be announced “at a later date.”