John was brought up in a small town between The Lake District and The Yorkshire Dales. Coming from a family of hill sheep farmers and dairy farmers, John spent much of his childhood helping local sheep farmers at lambing time and at gatherings and decided at an early age that he wanted to pursue a career working with animals.
Following a move to Edinburgh in 1969 to study for his HND in Agriculture and a brief spell working on a small farm back home, John became a Farm Research Assistant on a research farm run by the Animal Breeding Research Organisation (ABRO), a predecessor of The Roslin Institute. In 1994, he moved to the Large Animal Unit at The Roslin Institute and trained in large animal anaesthesia, at a time when the cloning experiments which led to Dolly were just beginning. His portraits in the Scottish National Portrait Gallery show his role as the anaesthetist during surgery in the research which produced Dolly. John was also the person who named Dolly after the singer Dolly Parton.
After over 40 years of service, John retired from The Roslin Institute in 2014.