It is hard to miss the church of St-Mary-le-Bow. Founded more than 1000 years ago, the church is famous for its towering steeple, still one of the tallest in London, and its bells. Anyone born within earshot was traditionally considered a true Cockney.
What is easy to overlook, however, is the small hole in one of the church’s stone walls, not much bigger than a hat box and flush with the ground. As my guide, the historian, writer and broadcaster Dr Matthew Green, points out, the hole once served as a glimpse into the outside world for those who chose to demonstrate their faith by being holed up inside the church’s walls.