Writer Anthony Horowitz based the character of Sam Stewart on his childhood nanny/governess, Norah Fitzgerald, who had been a WAAF driver during World War II, and used to tell Horowitz stories of her wartime experiences and exploits.
To the considerable mystification and annoyance of Anthony Horowitz (writer) and the cast, Simon Shaps, former Director of Television for ITV, who only stayed in the job for eighteen months, announced in 2007 that he would kill off this well-respected and lucrative series after making one final season of episodes. Horowitz had to abandon several scripts for episodes set in 1944, and jump forwards to episodes covering the end of the war in 1945. However in February 2009 it was announced that this decision had been reversed now Shaps had left his TV executive role, and three more episodes would be filmed. Foyle's War: The Russian House (2010), set in peace-time, was the first of these episodes.
The building used to film exterior shots of the "new" police headquarters in series 7 is adjacent to the one used for the exterior shots of the Sunshine Dessert Company, in "The Fall and Rise of Reginald Perrin" (1976). The buildings are located on Telford Way, in Acton, London, UK.