Chamberlain offers no Polish Guarantee.

Some recent works seem to imply that the Polish contributuion to ULTRA was a lot less important than they claim. Apparently British signal intelligence was already decyphering ENIGMA messages from the Condor Legion, so well before the handover of materials by the poles. Let's not forget ENIGMA was a commercial product, freely available on the market, the problem was getting the right settings of the rotors, so the story of the smuggled machines makes little sense, the key to decryption was knowing the procedures not having the machines.

 

And without the Sigint the machines are basically typewriters with clunky keys.

 

Its been said by many that the Enigma code breaking took 2 years off the war.

• ^ Kahn (1991).
• ^ [SUP]a[/SUP] [SUP]b[/SUP] Miller, A. Ray (2001). The Cryptographic Mathematics of Enigma. National Security Agency
• ^ Bletchley Park veteran and historian F.H. Hinsley is often cited as an authority for the two-year estimate, yet his assessment in Codebreakers is much less definitive: "Would the Soviets meanwhile have defeated Germany, or Germany the Soviets, or would there have been stalemate on the eastern fronts? What would have been decided about the atom bomb? Not even counter-factual historians can answer such questions. They are questions which do not arise, because the war went as it did. But those historians who are concerned only with the war as it was must ask why it went as it did. And they need venture only a reasonable distance beyond the facts to recognise the extent to which the explanation lies in the influence of Ultra." F.H. Hinsley, "Introduction: The Influence of Ultra in the Second World War," Codebreakers: The Inside Story of Bletchley Park, edited by F.H. Hinsley and Alan Stripp, Oxford University Press, 1993, pp. 12–13.