The world of music merchandising has experienced a seismic shift in the 21st century. Where once it would have been unthinkable to find band T-shirts for sale on the high street (HMV apart), it’s now par for the course, with retailers from River Island to Primark boarding the merch gravy train.

UMG-owned market leader Bravado, which reaches 44 countries and territories around the world, says its business is now split roughly 50-50 between live events and retail/online sales. The 40-year-old ...