Behind the polite frontages of many old streets lies a maze of courtyards, mews, and backlands where the real life of the neighbourhood once happened.

The way bricks are laid, and the size and colour of the bricks themselves, can date a wall, identify its builder's training, and even expose hidden alterations.

Before house numbers, a front door did the talking, announcing a builder's wealth, a family's taste, and the century they lived in.