Donald Vaughan Sinclair (22 April 1911 – 28 June 1995) was a British veterinary surgeon who graduated from the Royal (Dick) School of Veterinary Studies in 1933. He was made famous as the inspiration for the eccentric character Siegfried Farnon in the semi-autobiographical books of James Herriot (Alf Wight), adapted for film and television as All Creatures Great and Small. Royal Air Force service In 1939, Sinclair bought a veterinary practice at 23 Kirkgate, Thirsk, Yorkshire. In July 1940, he hired Alf Wight to run it while Sinclair was undertaking his war service in the Royal Air Force. However, in order to join up, Sinclair had claimed to be younger than he actually was. It was quickly discovered that his reflexes were not fast enough for him to continue with pilot training. He could have been redeployed within the service, but the fact that he was a veterinary surgeon meant that he was considered more useful to the war effort by resuming his peacetime profession. The severe national food shortage meant that proper veterinary treatment of farm animals received a high priority, and so within four months of joining the RAF he received a compulsory discharge and he returned to Thirsk. Veterinary practice Articles about Alf Wight shed more light on the start of the relationship between the two vets. When Sinclair was to leave for RAF training, he gave Wight all the practice's income in return for looking after it during his absence. His brother, Brian Sinclair (Tristan in the books), was not then qualified. After Sinclair was discharged from the RAF four months later, he asked Wight to stay permanently with the practice, offering a salaried partnership, which Wight accepted. Literary portrayal The fictional character Siegfried Farnon is portrayed as outspoken, opinionated, bossy, quick to lose his temper, and also quick to blow over. He is nonetheless basically good-hearted and an animal lover, fond of riding, and infuriated by any suspicion of deliberate cruelty to animals. One recurrent theme in Herriot's stories was Siegfried's criticism of James's flaws, such as forgetting appointments or leaving instruments behind after calls, only for the reader to find that Siegfried is found guilty of the same things. He also is highly forgetful, frequently telling people things and then forgetting them within the same day, to his disbelief when told of this. When Wight's first book was published, Sinclair was offended by his