The world eventing chamption today announced the horse had sustained an injury sustained during training, and had consequently been withdrawn from Team GB for the games in August.

A reserve rider and horse combination will now be selected by the British Olympic Association, after nomination from the British Equestrian Federation (BEF).

Phillips, 27, said: "I am very disappointed not to have the opportunity to ride at the Olympic Games and feel that Toytown deserved his chance to go.

"However, with horses these things happen and we still have a very strong team, I wish them every success."

Simon Clegg, Team GB 2008 Chef de Mission said: "This must be a huge disappointment to Zara particularly following the pair's success over the last few years. Naturally we now need to focus our full support on the rest of the team including Zara's replacement and give them every opportunity of competing to their full in Hong Kong."