German prisoners of war were interned at a camp near the 136th Station Hospital, and Italian prisoners were located at a camp at the nearby village of Borley. USAF personnel from bases at Lakenheath, Mildenhall, and Wethersfield airbases often lived within Long Melford. By the end of the war, two B24 Liberators, one B17 Flying Fortress and one RAF de Havilland Mosquito had crashed in the parish with over twenty persons killed or injured. Numerous pillboxes and temporary gun emplacements were constructed in the village during the war, and in 2012 a previously unknown underground bunker room was located. According to the Remembrance Plaque at Holy Trinity Church, ninety-six serving villagers were killed in World War One, and eleven during World War Two.
