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 approximately in depth. Soviet mobile formations were moved out of the salient and a large reserve force was formed for strategic counter-offensives. The Battle of Kursk was the first time in the Second World War that a German strategic offensive was halted before it could break through enemy defences and penetrate to its strategic depths. The maximum depth of the German advance was in the north and in the south. Though the Red Army had succeeded in winter offensives previously, their counter-offensives following the German attack at Kursk were their first successful strategic summer offensives of the war. As the