As I remember the British told Stalin what they knew but not how they knew it, so Stalin was suspicious. In the end kursk was the opposite of Blitzkrieg, the Russians knew exactly what the Germans would do with or without Enigma. I think the Battle of the Atlantic and D Day (to name just 2) would have run very badly without Enigma!
The Russians also had some effctive spy rings operating both in Germany and England. The most well known (though iit remains shrouded in secrecy even today) was the Lucy spy ring
The Lucy Spy Ring was an anti-Nazi Germany information network that operated out of Switzerland. A better way of describing it would be a series of inter-connected networks operating in several countries with the goal of bringing about the downfall of the Nazi regime.
The ringleader of the ring was Rudolph Roessler , the owner of a small publishing firm called Vita Nova. Roessler was approached by two German officers (Lieutenant General Frtiz Thiele, the German Deputy Head of Communications and Rudolph von Gersdorf, (chief of Intelligence Army Group Centre) who were a part of one (of many) plots to overthrow Adolph Hitler. They persuaded him to act as a channel for high level military intelligence information, equipping him with radio equipment and an Enigma machine. They also had him designated as a German military station, enabling him to receive their transmissions through normal broadcast channels.
Roessler passed the information to Swiss Military Intelligence which in turn passed it along to the British SIS. Recognizing that the Soviet Union was an important partner in bringing down the Nazi's, Roessler passed information directly to the Soviets through a Soviet GRU spy network run by Sandor Rado . Rado knew of Roessler only through his code name "Taylor" and that he was broadcasting from Lucerne, Switzerland and thus labeled the broadcasting network "Lucy."
Roessler passed along significant information starting with the details of Operation Barbarossa. Germany had planned to invade the Soviet Union but the Lucy network got the information to Soviet intelligence in May 1941, causing the Soviets to recognize the immense value of the Lucy network. The network continued to funnel high-grade military intelligence to the Soviet regarding invasions of Stalingrad and Caucausus and the German Plans for Operation Zitadelle allowing the Soviets to repel the German offensive on the eastern front and changing the course of the war.
One of the major feats of the Lucy network was the speed with which was able to deliver the information, with information from Germany arriving in Soviet hands in under ten hours. Hundreds of messages were passing along the channel each month with Roessler doing the bulk of the work on his end and Allan Foote, Rado's main radio operator, on the other.
By 1942 Germany had become aware of Rado's transmissions through their counter esionage work against the "Red Orchestra network. They attacked the Lucy network's legitimacy through the Red Orchestra counter-espoinage program. Eventually, they used military and political pressure on the Swiss government to shut down the Lucy network. Swiss authorities arrested several network participants in October 1944 and the German officials who were supplying the information were arrested after the failed 20 July plot to assassinate Adolph Hitler.
An air of controversy surrounds the Lucy network years after it was dismantled. It has been alleged that the Lucy network was in actuality an operation created by the British Secret Service, but most historians dismiss this notion. What is indisputable is that the Lucy network provided essential and invaluable intelligence information to the Allies during World War II, specifically getting information to the Soviet Union and allowing the Soviets to turn the tide of the war around.
"Red Orchestra" is a complex and often contradictory story ....
The Red Orchestra | WW2 Resource