Zara Phillip retired from competing at the Badminton Horse Trials after making a mistake on the cross-country course.
After a good start during yesterday's dressage stage, Phillips - who was riding High Kingdom - missed the second of two brush jumps in the Lake and pulled up.
It means she can no longer take part in tomorrow's show jumping stage.
For more on the Badminton Horse Trial visit the ITV News West Country (E) website.
Zara Phillips put herself firmly in contention at the Mitsubishi Motors Badminton Horse Trials today with a quality dressage performance on her London 2012 horse High Kingdom.
Phillips, the Queen's granddaughter, posted a dressage score of 44.3 penalties that kept her firmly in touch with the leading group midway day two.