One puff adder, one antelope, one crocodile - This was the list of sick animals presented to Oliver Graham-Jones on his first day as a new vet at London Zoo in 1951. And his time at the zoo didn't get any less strange or entertaining. There's the time he anaesthetized, and was then chased by, a gorilla; had to capture an angry polar bear in thick fog; performed a colostomy on a python; and fitted a raven in the Tower of London with a wooden leg.

And if an animal escaped (more frequently than you might think) or required urgent medical attention, he was always on hand, ready for any eventuality. With his self-deprecating humour, Oliver frequently described himself as quaking with fear, but he was also skilful, brave and, most of all, incredibly caring and kind to his animal patients.