I’ve been intrigued by Cornwall’s blue sharks since reading about them as a child, but I never thought I’d see one. Especially not up close and personal like this. It’s a stunning specimen too, a two-metre-long female, circling cautiously in a wide arc around the boat. After a few, too short minutes, it’s time to leave the cage and let the other divers enjoy this thrilling, ethereal encounter. Which they do, very much.