The 28-year-old, who is the daughter of eventing legend Lucinda Green, was on site at the event with her 15-year-old ride Malin Head Clover, known at home as Ali G, when she broke the news that he was going to be unable to compete.
She posted on her Instagram page shortly before the first horse inspection was due to get under way: “Sadly I have had to withdraw MALIN HEAD CLOVER (Ali G) from [Burghley Horse Trials].
“I am in total shock, he has felt brilliant in this whole lead up, he was sound this morning on our wonderful ride together through Burghley Park and now, for whatever reason, he is not.
“I have no idea why or how this has happened – it could be anything from a bang in the stable to something in his foot to God knows what. Although not immediately obvious, it is there and I can’t risk competing my beloved boy in this condition.”
Lissa has been sharing her Burghley preparations with Horse & Hound readers in a guest blog on the website, in which she explained the lengths she had gone to to ensure that both herself and her ride were in tip-top condition.
She closed her Instagram post by saying: “What makes this even worse is that this was always going to the Ali’s last top level competition. I can’t believe we don’t get to do it together, we were really looking forward to going out on a high. ❤ Love you Ali ❤”
Find out the forecast for this year's Land Rover Burghley Horse Trials
Lissa Green, who will be tackling her first Burghley in just a few weeks, introduces herself and her remarkable little…
Lissa lets us know how she has been getting herself fit and prepared for her imminent Burghley debut
Lissa made her four-star debut at Mitsubishi Motors Badminton Horse Trials in the spring, jumping round the cross-country course with one stop. However, she had to withdraw from the holding box at the trot-up the next morning when Malin Head Clover was unlevel.
Lissa’s mother Lucinda won Burghley twice, in 1977 on George — when the event also hosted the European Championships — and in 1981 on Beagle Bay.