Joel Greenberg

Ronald Lewin notes on interview with Stuart Milner-Barry
Sent to Gordon Welchman – 21 April 1977

Sir Stuart Milner-Barry
1.    He was an exact contemporary of Welchman’s at Trinity. He joined B.P. in early’40 about the same time as Alexander. His memoir of Alexander, which he loaned me, gives all the circumstances. In a general discussion of the first nine months of B.P. he emphasised that Welchman was the salient figure. Apart from his mathematical skill, he stressed his quality of foresight and the drive to make preparations whose need he foresaw but others didn’t. He said that in this, Travis was a great strength. W. had many battles with him over staff, equipment, etc., but whenever T. grasped the point he backed W. We discussed Denniston’s role and he confirmed that whatever his cryptological past he was. As he put it, “a busted flush” by that Winter and incapable of the organisational effort that was necessary if B.P. was to be put on a war footing. It was this that he considered to be W’s personal achievement. We discussed the April breakthrough and he confirmed that W. had achieved this by working specifically on the preliminary items in the intercepts (1) and ignoring, unless for any specific reason, the actual text of the signal. He made clear to me as I had not understood before the nature of the discriminant, identifying the one of six possible settings, and the difference between this and the random coding which gave the setting for the specific individual signal. He reminded me too that the date and call-sign were important indicators. He said that when the first breaks occurred there was disappointment because the plain texts produced were practice messages, nursery rhymes and so on, but he said it was Welchman’s vision which appreciated that actual signals would soon be coming in and it was W. who insisted that from then on a three-shift system must be introduced – as it was. He had little to add to what I already knew about Knox and Turing.

2.    We discussed intake during the Norwegian and French campaigns and I described to him the large claims of Bertrand and the Poles. He could give me no rational explanation for these but agreed that if, as I understand it, B.P. was concentrating in the technical side because of its more sophisticated equipment, while Vignolles was concentrating on actual de-ciphering based on keys supplied from B.P., then there could have been a lot of decipherment at Vignolles of which he was not aware in Hut 6. Nevertheless he agreed on the inherent improbability that a mass of genuinely important signals were being deciphered in this period. So the matter still remains  obscure.

3.    He agreed that Denniston had to go and that in his experience, Travis, with all his limitations, had the organisational grasp necessary to control the rapid expansion at B.P. He was not clear about D’s functions when he was transferred to Berkeley Street. I said I had the impression that he was there concerned with diplomatic traffic (I didn’t remember to say so but Telford Taylor told me that when he first came over in ’43 he spent some time there with D. on diplomatic matters). When I asked whether German diplomatic was deciphered as, for example, was the Japanese diplomatic on Purple, he said he thought not and indeed had it been so one might have expected that Hut 6 would have been involved. My present presumption, to be checked, is that German diplomatic was in code or a cipher not Enigma.

 

4.    We discussed Menzies. He said he was aware of his occasional presence though he was always remote. He agreed that M. was probably astute enough to realise that Ultra was the intelligence element that he must grasp to himself (he had after all been in the picture at least since the Warsaw meeting in the summer of 1939), and that he must have realised that the old traditional methods of S.I.S. could not conceivably produce comparable results. He recalled an episode which he placed some time in pre-Battle of France period but which could only have occurred sometime after May 10 when Churchill became Prime Minister. He said that there was great frustration in Hut 6 about inability to obtain sufficient staff and equipment, and that Welchman wrote a letter to Churchill, saying that it was no good addressing it to anybody else, which M.B. and Alexander signed. M.B. then proceeded to London where he took a taxi to No. 10 and handed in the letter to one of Churchill’s staff. The consequence was a marked improvement in the situation (2). It also produced a not intolerable rocket from Denniston and Menzies. M.B. said that he thought in fact they were rather amused and rather pleased in spite of the by-passing of the chain of command. I pointed out that it was probably a good thing that they were on the Foreign Office strength and not, like others at B.P., either Army or Navy in which case reactions might have been severe.

 

5.    He recalled a visit by Winston to B.P., which he placed in 1941, and he remembered Winston standing by the lake and addressing the assembled company, beginning with the words “You all look very innocent”. He also said that Welchman had prepared three points to make to C. when he was being shown around Hut 6. Time was short, and after the second point had been made Menzies or who ever said that was enough and tried to move W. on. But C., with a wink, turned to Welchman and said “But I think there was a third point”.

6.    We discussed Crete and I explained the problems. He instantly said that he had absolutely clear recollection of having in his hands three weeks before the invasion began an intercept giving the complete Operation Order for the invasion. I pressed him on three weeks and he was quite firm. He said also that the feeling then was that “we had got them” in the sense that intelligence about the invasion of an island ought to enable us to repel it. And he described the disappointment  at B.P. with the final results. He could recall nothing, however, about what is said to be the enquiry set up by Churchill after Crete into the dissemination of Ultra to commanders in the field.

7.    Bismarck: He strongly questioned the view that Ultra had nothing to do with it. He said that he knew of the sinking of Hood through the intercept of a signal to Kesselring in (?) Greece (CHECK Kesselring‘s movements at the time with Macksey who is writing his biography). He said that on the day before the sinking he also saw a further signal to Kesselring giving Bismarck’s intention to proceed to Brest and, he thought, her current position. Most importantly, he recalled with absolute clarity a visit by Admiral Pound (3) to B.P. after the sinking to give a thanks for assistance provided. On accepted calculations the deductions are, (a) that some concrete intelligence was certainly provided from B.P. According to M.B., this was the only occasion he could remember when Pound went down to BP and it was not his nature to do that sort of thing without good reason. (b) the most likely application of a B.P. decrypt in the chain of events may well be that it was the reason for the despatch of the Catalina which ultimately spotted Bismarck. Who was the pilot? Is he alive? What was his brief? (c) It is possible that the case made by Beesly, Denning and the other O.I.C. people is vitiated by the fact that they are preoccupied with intelligence coming from the naval section at B.P. whereas the Kesselring traffic would presumably be on the Red Luftwaffe cipher which we read so easily. That B.P. was closely involved in the hunt is emphasised by MB’s recollection that when we lost touch with Bismarck and everyone was at panic stations he recalls that immense pressure was put on B.P. to be alert for any possible clue.

8.    He emphasised the basic point that the whole Ultra operation was a knife-edge one and that results were discontinuous. In a vivid personal point he recalled how, when there was a delay in achieving a break, his heart would sink when he went on watch all the machines were silent.

9.    An important practical point. He said that when he was in charge of Hut 6 and Alexander of Hut 8 their close personal friendship was of great importance in enabling them to avoid the competitive tensions between the requirements of the naval people and those of Hut 6, particularly in regard to such matters as priority in the use of the Bombes. These are points which tend to be overlooked by historians without operational experience, and a good analogy in this case would be a situation when Slim arrived in Burma to take command of the Retreat and found that the two commanders of the Divisions in Burma Corps were old friends who had served with him in the same battalion of First 6 Gurkhas.

10.    The Ardennes: Having agreed that once Normandy was over Ultra was of no great interest and even, at Arnhem, a failure, we talked about the Ardennes. I told him about the prevailing climate of opinion at the Front and the assumption that the war was nearly over which prevented intelligence officers from being on the alert, and said that my impression is that a similar attitude prevailed at B.P., giving instances. He agreed, and said that when the offensive started he went to the Chiefs to find out what had gone wrong and ask how he could keep up the morale of those in Hut 6 who were knocked sideways by this enemy success at time when things were going so well.

11.    But things, he said, were not going so well at the end. He said that about April ’45 the Germans introduced a new wheel into Enigma. I could not follow the technical explanation he gave because it didn’t add up. He said that a new wheel was produced for the Umkehrwalze but John Monroe a week or two ago had told me that the putting of the Umkehrwalze on a rotor had been the reason for the failure to get back into the Atlantic U-Boat cipher throughout 1942. Could it be that this was simply a routine extension of this earlier modification of the U-Boat Enigma or the Enigmas used for other ciphers? It smells like a routine change rather than one based on suspicion, because M.B. said that though we were despondent when the change occurred we were able to keep going because the Germans could not distribute simultaneously to all their stations this additional wheel. Consequently signals would be transmitted in the new cipher and then re-transmitted in the old cipher to stations which had not been converted. Thus enabling us at least partially to hold our own. By V.E. Day, however, he said that we were pretty well out of the picture. The point he made was that to master the new cipher would have involved a substantial or complete modification of the existing Bombes and he placed the delay involved at about six months. Thus it is ironic that in the moment of military victory we appear to have been in a phase of technical defeat. Query: When Oscar Oeser was sent out to Germany immediately before the collapse to grab information and equipment was he under instructions to get hold of the latest model of the machine? In the account he gave me it is interesting that he was pressing so hard to lay hands on the station still known to be operating in the Redoubt, and particularly pleased when he got hold of Kesselring’ command train containing four of the latest Enigmas.

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(1)  This was the unencrypted information such as the call sign of the sender and the frequency the message had been sent on

(2)  This is confirmed by Kahn in Seizing the Enigma

(3)  Dudley Pound, First Sea Lord

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Image:  Stuart Milner-Barry, playing chess, 1952.

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