The Queen s 41-year-old granddaughter was cheered on by both her father, who turns 74 this month, and Florence Standaert - a Belgian equestrian thought to be in her 40s.
Phillips was pictured driving to the event with Belgian equestrian Florence Standaert, who is thought to be almost the same age as the former Olympic medallist s daughter, Zara Tindall, 41.