Forty years ago to the day, 7 September 1940, Hurricanes of 257 Squadron took off from Martlesham Heath, Suffolk, to intercept a wave of Luftwaffe bombers over the Thames Estuary. Among those lost in the engagement that followed was ' A ' Flight commander, Fl-Lt H. R. A. Beresford. No one saw him shot down and his body and aircraft were not recovered. He was posted as ' missing
But in September 1979 a group of enthusiasts in Second World War military aircraft, located beneath the mud of the Isle of Sheppey what they believed to be the wreckage of a fighter ... This documentary pieces together the story of Beresford's last mission.