Yuri Modin was a KGB agent. He was the controller for ring of Soviet spies in England known as "the Cambridge Five." The five include:
– Donald Maclean, who passed (among other things) atomic secrets to the Soviets. Maclean was first secretary of the British embassy in the US. In addition to atomic secrets he passed on lots of information on US and British goals for the various conferences of the big three. Stalin, in other words, knew what FDR and Churchill wanted before they sat down together (in at least one case, Modin says that Molotov got his counterparts’ briefing materials before they did). There’s more in Wikipedia if you can stomach it. Happily for Maclean, he defected before he would have been captured and lived out the rest of his life in Moscow. Maclean’s father was education minister in Ramsay MacDonald’s government.
– Kim Philby, who ran the counter-intelligence section of MI6 (i.e. the area that was responsible for analyzing British intelligence on the Soviets and stopping the activities of the KGB), helped the Americans set up the CIA, and was the top British intelligence official in the US for a time (he was the liaison between MI6 and the CIA). Obviously these positions make Philby the worst placed spy ever. He also fled to the Soviet Union and is buried there. Philby was booted from his intelligence positions when he came under suspicion, but he found work writing for The Economist, among other papers.
– Guy Burgess, who was also a British intelligence agent. Also, Burgess worked at the BBC for a while. Burgess died in the Soviet Union.
– Anthony Blunt, who was a historian and art critic after he was an intelligence agent. His father was a Church of England cleric and Blunt himself was related to the royal family. He was knighted, but was stripped of his knighthood, which I believe is the full extent of all the punishments these men received. Wikipedia notes that his friends (e.g. the Rothschilds) were not much concerned with his espionage activities.
– John Cairncross, who was also and intelligence agent (also counter-intelligence) and passed on some information about atomic weapons development. Most interestingly, Cairncross was in the section responsible for the finances of NATO, so he knew what weapons were where and basically everything else about NATO. Wikipedia notes that all three of his brothers were professors. After his exposure, Wikipedia notes that Cairncross moved to the US and lectured at Northwestern. Later he worked for the UN. (That’s Wikipedia, not me making stuff up that I would like to be true). The Russians never broke enigma, but they never needed to thanks to information passed on by these (and other) spies.
This collection of spies constitutes perhaps the best in the history of espionage. Given how well-placed they were, it would probably be easier to figure out what the Soviets didn’t know about US and British plans than what they did know. The spies all escaped capture because they were so well-placed that they found out about the breaking of Venona, and thus knew when they would be captured.
As Modin notes, "the most baffling part of all was that the Five were typical representatives of their nation and their class." Perhaps it’s not so baffling.
Please always remember, none of this withstanding, that Joe McCarthy was crazy.