The purest barometer of Ben Ainslie’s America’s Cup success is not in feedback from his Ineos Britannia’s billionaire backer Jim Ratcliffe, nor in the warm-up regattas to this year’s event. Instead, it rests on the shoulders of a seven-year-old Wimbledon schoolgirl.
Bellatrix is the team’s biggest detractor, and also the elder of Ainslie’s two children.
