In the documentary The Queen at 90, Sophie, Countess of Wessex explained her mother-in-law’s penchant for rainbow shades. “She needs to stand out for people to be able to say ‘I saw the Queen,'” she said.
“Don’t forget that when she turns up somewhere, the crowds are two, three, four, ten, 15 deep, and someone wants to be able to say they saw a bit of the Queen’s hat as she went past.”