Saturday, 9.30pm, History In the years since World War II, US intelligence has steadfastly refused to declassify the work of the unit known as MIS-X (Military Intelligence Service-X), based at Fort Hunt, Virginia. This intriguing documentary explains how the unit, modelled on Britain’s MI9, trained American pilots to send back coded messages if they were captured by the Germans. It even managed to hide maps, money, compasses, radios and guns inside humanitarian parcels from fictitious charities sent to prisoners of war. The unit maintained communication with US airmen in 64 German camps and helped 737 soldiers escape. Disbanded after the war, its incredible work has remained top secret — why?