He's been in his government's service for years, protecting that gem of the crown jewels, St. Edward's Crown, as his singular duty: "the keeper of the crown".  He may no longer be as spry and healthy as some of the guards and yeoman warders who are assigned to the Tower of London, but he is still as committed to his duty as the day he was assigned to it.  And he's pretty dangerous with his cane even though he's totally blind!