supplied by Naval Section and failed to come out; 'Hinsley’s certain cribs' became a standing joke. After consulting many people I have come to the conclusion that it is impossible to get an impartial and moderately accurate picture of cribbing attempts at this period: Hut 8 and Naval Section each remain convinced that cribbing failures were due to the other section's shortcomings.
1940 was clearly a very trying period for those outside Hut 8 whose hopes had been raised by the April Pinch and the results obtained from it. On August 21st Mr. Birch wrote to Commander Travis: "I'm worried about Naval Enigma. I've been worried for a long time, but haven't liked to say as much.... Turing and Twinn are like people waiting for a miracle, without believing in miracles.....
"I'm not concerned with the cryptographic problem of Enigma. Pinches are beyond my control, but the cribs are ours. We supply them, we know the degree of reliability, the alternative letterings, etc. and I am confident if they were tried out systematically, they would work.
"Turing and Twinn are brilliant, but like many brilliant people, they are not practical. They are untidy, they lose things, they can't copy out right, and they dither between theory and cribbing. Nor have they the determination of practical men......
"Of the cribs we supply, some are tried out partially, some not at all, and one, at least, was copied out wrong before being put on the machine.....
"Sometimes we produce a crib of 90% certainty. Turing and Twinn insist on adding another word of less than 50% probability, because that reduces the number of answers and makes the result quicker. Quicker, my foot! It hasn't produced any result at all so far. The 'slower' method might have won the war by now.
"Presumably the number of answers possible on a given crib is mathematically ascertainable. Suppose the one we back 90% has 100,000 possible answers: is that a superhuman labour?......
"When a crib, with or without unauthorised and very doubtful additions, has been tried once unsuccessfully we are not usually consulted as to what should be tried next, but, generally speaking, instead of exhausting the possibilities of the best crib, a new one is pottered with under similar handicaps. No crib has been tried systematically and failed; and a few have been tried partially and the partial trial has been unsuccessful.....
"Turing has stated categorically that with 10 machines he could be sure of breaking Enigma and keeping it broken. Well can't we have 10 machines?.....
"At one end, we're responsible for cribs; at the other end
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