Since our appointment as ‘best friends’ to the Duke and Duchess of Cambridge we were now expected to behave with decorum at all times.

Prince William was such a joker that we struggled to keep our cool when we accompanied him and his wife to solemn events. Once he threw a cheeky smile and winked at me at an outdoor ceremony to commemorate the end of World War I. I almost lost it, but somehow managed not to collapse to the ground in a fit of giggles.