In mid-December 1941, Driscoll finally sent the British some information on her special method, with only cursory answers to the few questions Denniston had posed four months before. Driscoll again declared her faith in her approach, but GCCS concluded that it “apparently failed.” For one thing, it could not, as she had claimed, overcome the problem of turnover — that is, the tumbling of the Enigma’s wheels before enough letters had been enciphered to identify the wheel being used. And as Turing pointed out to her in a letter in October 1941, her method would take seventy-two thousand hours — more than eight years — to find a solution. Given Driscoll’s obstinacy, Bletchley park began to have second thoughts about providing more technical information.

As luck would have it, an apparent mix-up in the mail delivery between OP20G and Bletchley Park soon brought the simmering distrust and jealousies between the two agencies flaring the the surface. Dennison’s early October dispatch — a bag of materials containing detailed answers to all but one of Driscoll’s questions — never reached OP20G, the Navy claimed. It didn’t take long for Safford, who feared the British were breaking their promises, to push Leigh Noyes into firing off a series of complaints to the British. Through November and December 1941, angry memos and accusations flew across the Atlantic. Noyes didn’t mince his words: Britain had broken its promise to OP20G; American had no use for the Bombe; and if GCCS cooperated, Driscoll could have her method working on real problems. …

Noyes, who was unaware of the complexities of the mail mix-up, continued to fire off angry memos to the British, some of them clearly threatening. The U.S. Navy, he said, had never agreed to confine itself to Enigma research. It had always intended to be “operational” — that is, intercepting and decoding messages on its own. He told Hastings that all the Navy wanted from the British was the information on the Enigma and the codebooks and Enigma machine that Safford and Driscoll had requested.

Then, belying later histories of GCCS and OP20G relations, Noyes apologized to the British, twice. On December 10 and again on the twelfth, he declared that British explanations and actions since his outbursts had satisfied him and “everyone” at OP20G. The missing package, of course, was found. On December 13, Bletchley received a cryptic yet pointed message from someone in the U.S. Navy Department: “Luke Chapter 15, v 9: And she found it. She calleth together her friends and neighbors saying: Rejoice with me for I have found the piece which we lost”.

— Jim DeBrosse, Colin Burke: The secret in Building 26