The movie, set during the Second World War, features a daring escape scene where Steve McQueen's prisoner of war character attempts to jump to freedom over a barbed wire fence, using a stolen motorcycle. McQueen wanted to do the stunt himself, but in the end it was stuntman Bud Ekins who completed the jump. And the reason for choosing a Triumph bike was simple: military bikes from the 1940s couldn't have been used to successfully perform the stunt, and so the film crew acquired Triumphs that were suitably agile, and distressed them to look right for the film.
This particular bike is one of three used for filming. Before it was put up for display at Triumph's Factory Visitor Experience, the 1962 650cc TR6R hadn't been shown publicly at all, and the Blenheim Palace event is one of its first major outings after filming was completed. The bike will be judged at the event's Class B, which is dedicated "Exceptional Motorbikes" from 1940 to 1979; the event is held from August 30th to Sep 1st.