One hundred years ago, it was common for streets to be filled with whistling – the crying call of milkmen and builders on construction sites, everyday people going about their business. It was so popular that in the late 19th and early 20th centuries, music halls would host professional whistlers – souffleurs – and bans on whistling had to be enforced in coal mines. Beyond the enjoyment of music, whistling was a means of communicating with your fellow sailor on the rigging, and – more grimly – your partner in concentration camps. So, what happened to this tradition? Professor of Music at the University of York Rachel Cowgill, says while the streets are now quieter, a keen core of whistlers remain. She speaks to Jim.