In 1939, Sinclair bought a veterinary practice at 23 Kirkgate, Thirsk, Yorkshire, and he hired Wight to run it in July 1940 while Sinclair was undertaking his war service in the Royal Air Force. However, Sinclair had deliberately misrepresented himself as being younger than he was in order to join up, and 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 very high priority, and so within four months of joining the RAF he received a compulsory discharge and he returned to Thirsk.
Literary caricature
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 tools behind after calls, only for the reader to find that Siegfried is found guilty of the same things. When Wight's first book was published, Sinclair was offended by his portrayal and said, "Alfred, this book is a real test of our friendship." Things calmed down, however, and the pair continued to work together until they retired. Wight's son stated in The Real James Herriot that Sinclair's character in the novels was considerably toned down, and that Sinclair was even more eccentric than the Herriot books portrayed.
Death
Sinclair took his own life by an overdose of barbiturate on 28 June 1995 at his home Southwoods Hall, near Thirsk, two weeks after the death of his wife Audrey, to whom he had been married for 53 years. His brother Brian had died several years earlier, and his friend and partner Alf Wight only four months previously.
