Battle of Kursk guns and mortars. In 1943 an offensive by the Soviet Central, Bryansk and Western Fronts against Army Group Centre was abandoned shortly after it began in early March, when the southern flank of the Central Front was threatened by Army Group South. Soviet intelligence received information about German troop concentrations spotted at Orel and Kharkov, as well as details of an intended German offensive in the Kursk sector through the Lucy spy ring in Switzerland. The Soviets verified the intelligence via their spy in Britain, John Cairncross, at the Government Code and Cypher School at Bletchley Park, who clandestinely forwarded
Battle of Kursk a small area in the immediate environs of Kursk. The combined depth of the three main defensive zones was about . The six defensive belts on either side of Kursk were deep. If the Germans managed to break through these defences they would still be confronted by additional defensive belts to the east, manned by the Steppe Front. These brought the total depth of the defences to nearly . The Voronezh and Central Fronts dug and of trenches respectively, laid out in criss-cross pattern for ease of movement. The Soviets built more than 686 bridges and about of roads in