All Creatures Great and Small (TV series) that be wanted to cast the role. Sellars, instead, asked Timothy if he would accept the role of Tristan Farnon. "I had a wife, I had children, I had a mortgage to pay, and I wasn't working. So I said, 'No. It's Herriot or nothing.'" Timothy put everything on the line. "I got home one night, at about 9 o'clock. My wife was washing up in the kitchen. I walked into the kitchen and she said, without turning round, 'You've got the Herriot part.'" Timothy also stated that, after all of the roles had been cast except that of Herriot,
Donald Sinclair (veterinary surgeon) Donald Sinclair (veterinary surgeon) Donald Vaughan Sinclair (22 April 1911 – 28 June 1995) was a British veterinary surgeon (graduated from the Royal (Dick) School of Veterinary Studies, 1933) made famous as the eccentric character Siegfried Farnon in the semi-autobiographical books of James Herriot (Alf Wight), later adapted for film and television as "All Creatures Great and Small". In 1939, he bought an existing veterinary practice at 23 Kirkgate, Thirsk, Yorkshire, and in July 1940 hired Wight to run it while he (Sinclair) was undertaking his war service in the Royal Air Force. However, Sinclair had deliberately misrepresented himself as