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Battle of Kursk which showed the Red Army constructing very strong positions at the shoulders of the salient and having withdrawn their mobile forces from the area west of Kursk. He argued that the longer the preparation phase continued, the less the operation could be justified. He recommended completely abandoning Citadel, allowing the army to await and defeat the coming Soviet offensive, or radically revising the plan for Citadel. Though in mid-April Manstein had considered the Citadel offensive profitable, by May he shared Model's misgivings. He asserted that the best course of action would be for the German forces to take the strategic