The Bombardment of Mailly-le-Camp was an RAF raid against a German panzer training center located in northern France undertaken during the night of 3/4 May 1944. The mission was a part of the "softening up" campaign Bomber Command conducted prior to the D-Day invasion. The operation was assigned to No. 5 Group, which was joined by No. 1 Group. Estimated a lightly defended target, confusion in the mission plan and communication problems led to the force being held up at the assembly point, where German night fighters slipped in among the bombers. Though the bombers succeeded in destroying the training camp, the victory was achieved at a heavy price.