Waiting for my annual rendezvous with my optician, I am looking down at Smelly Alley, the best known walkway in Reading. Narrow and dark, crowded and loud, it stretches between Broad Street and Friar Street, the parallel spines of the town’s medieval core. The perfume that gave it its name is a heady mixture of thawed fish, rotten vegetables, cheap shoes, sausage that defies classification, and perpetual puddles of many a wicked hue. Directly under my perch, practically within reach but behind sealed glass, the alley now smells and now smells not. Sitting in an air-conditioned waiting room, I cannot make out whether the fickle whiff comes my way by way of my nose or my eyes.