Read The Secrets of Station X Online
Authors: Michael Smith
Given the RAF’s approach to the codebreakers, which was
epitomised
by Blandy’s initial insistence that Cheadle should not get involved in producing ‘stuff for people at Bletchley to fool about with’, the refusal to allow the Bletchley Park Air Section
to send out intelligence reports was perhaps less of a surprise than it should have been, but Josh Cooper found a way round the problem. He attached his own people to each of the wireless intercept shifts at Cheadle to break the basic
Luftwaffe
codes alongside the operators with Air Intelligence, agreeing that they could provide intelligence rather than the raw signals. These would have otherwise been largely unintelligible to their
recipients
, who included RAF Fighter Command at Bentley Priory north of London, from where the fighter defences were
controlled
. ‘I applied to the Air Ministry for a number of Computor Clerks,’ Cooper said. ‘This curious title had nothing to do with electronic computers, which had not yet been invented, but was an echo of an old War Office covername for cryptanalysts – Signal Computor. A successful Computor Clerk watchkeeper was going to need considerable initiative, and would have to fit in with the special world of Cheadle radio operators.’ The ‘Computors’, as they were known, were trained up at Bletchley before being sent to Cheadle and the move proved highly successful, said Bonsall.
Arriving shortly before the Germans invaded Western Europe the ‘Computors’ soon achieved their primary task of breaking the air/ground codes completely and quickly enough to derive current intelligence from them. The original three-letter codes were replaced in 1941 by three-figure codes. These codes were harder to break but the ‘Computors’ developed techniques which resulted in their being broken quickly and completely enough to yield intelligence. To begin with, the ‘Computors’ worked in the main set-room, with the result that their raw material reached them quickly and the operators could see that their intercepts were eagerly awaited.
The
Luftwaffe
low-level communications between the aircraft and ground controllers were intercepted by Cheadle and, increasingly as the
Luftwaffe
communications switched to
VHF, by a network of small RAF mobile and fixed Home Defence Units based along the eastern and southern coasts at Peterhead and Fifeness in Scotland, Blyth in Northumberland, Scarborough, Skegness, Gorleston, Harwich, Fairness, South Foreland, Hawkinge, Beachy Head, Portsdown Hill, Portland Bill, Strete (near Dartmouth), Coverack and Hartland Point. This network, which was coordinated by RAF West Kingsdown in Kent, provided vital tactical intelligence on the preparations of the German bombers and their fighter escorts. Bletchley gave advance notice of the planned times of raids, the intended targets and the numbers of aircraft involved.
The introduction of the ‘Computor Clerks’ to Cheadle had allowed Cooper to find a way around the RAF chiefs’ perverse view that one of their own intelligence branches should not be allowed to produce intelligence. Under his direction, the Bletchley Air Section had complete mastery of all the
Luftwaffe
low-grade codes and cyphers. ‘Its cryptanalytic achievement was formidable,’ said Birch. ‘With far more lower grade German material to deal with than the other Service sections, it could claim at the end of 1940 that all known
Luftwaffe
non-machine cyphers were readable; of meteorological cyphers, four German, five Russian and two Italian had been read.’ Cooper was an extraordinarily astute man whose career in signals intelligence, or Sigint as it is known in the jargon of the codebreaker, went on to span the inter-war period, the Second World War and the Cold War, but he became known to many who arrived at Bletchley during the war as one of the more unusual of the senior staff.
Ann Lavell, who arrived at Bletchley in July 1940 as an 18-year-old WAAF, became Cooper’s PA. She recalled that he had a distinctively nervous habit of putting his right hand behind the back of his head and stroking his left shoulder. She found his eccentricity difficult to deal with. ‘He was absolutely mad, frightening really,’ she said.
At first I didn’t like him at all. I thought he was horrible. But
when I got to know him I got quite fond of him. But he was not really one of us. He was on another plane, I think. He’d get awfully embarrassed and worried when he felt he wasn’t acting like an ordinary human being. There was one time when he kicked over a fire extinguisher and it started foaming and he didn’t know what to do and he picked it up, rushed to and fro, and a friend of mine went and took it from him and put it out of the window. He wasn’t very practical but once you knew him and got over the slightly forbidding exterior he was very nice and very kind. I’ve got a rather delightful caricature of him, doing this very familiar gesture of right hand behind head and scratching left ear.
Once they were standing beside the lake and Cooper was
drinking
a cup of coffee. When he finished he stood there with the empty cup and was clearly slightly embarrassed by having it in his hand. ‘So he just threw it in the lake,’ Lavell said.
R. V. Jones recalled that Cooper was frequently asked to take part in interrogations of pilots. The first time he did this, he and two other interrogators were sat behind a trestle table when the captured
Luftwaffe
pilot, wearing perfectly pressed Nazi uniform and highly polished jackboots, was marched in and halted in front of them. ‘He clicked his heels together and gave a very smart Nazi salute,’ said Jones.
The panel was unprepared for this, none more so than Josh who stood up as smartly, gave the Nazi salute and repeated the prisoner’s ‘
Heil Hitler
’. Then realising that he had done the wrong thing, he looked in embarassment at his colleagues and sat down with such a speed that he missed his chair and disappeared completely under the table.
Gwen Davies, another member of the Air Section, remembered Cooper as being ‘a very, very strange man, who would burst into the watch sometimes and shriek something absolutely
unintelligible and burst out again’. Most of the junior members of staff had difficulty understanding what he was saying, but there was no doubting his brilliance.
There was a great degree of tolerance at Bletchley for
eccentricities
. There had to be because so many of the people were very, very eccentric indeed. At least half of the people there were absolutely mad. They were geniuses, no doubt many of them were extremely, extremely clever, but my goodness they were strange in ordinary life.
As the number of messages on the
Red
cypher dropped due to the decline in German offensive operations, Hut 6 had much less work but on 2 September 1940, a new Enigma key,
Brown
, was broken with the aid of Cillies and the newly introduced Bombe
Agnus Dei
. The messages in the
Brown
Enigma had risen during the late summer of 1940, when the Battle of Britain was in full swing and the RAF Hurricanes and Spitfires were fighting off the
Luftwaffe
daytime bombing raids, said Stuart Milner-Barry. ‘Nobody knew what its contents would be and the most extravagant hypotheses were entertained.’ The
Brown
traffic was found to be communications between a number of
Luftwaffe
stations in France which were directing wireless beams across Britain to guide the German bombers to their targets. It was a critical moment and the timing of the break could not have been more opportune. Having lost the Battle of Britain, the
Luftwaffe
was about to switch to the period of night-time bombing that would become known as the
Blitz
. The breaking of the
Brown
Enigma was to give Bletchley the first of a number of major contributions to the war effort.
‘It proved a delightful and a most entertaining key
cryptographically
,’ said Milner-Barry,
because although the traffic was small, the density of cribs and of Cillies was phenomenal. Never before or since have so many
and such gross breaches of the most elementary rules of cypher and procedural security been committed as by the specialists in beam bombing. They never learned and the German signals officers apparently were powerless to intervene. It was also extremely exciting because of course the object of the exercise was to discover the target before it was too late to be of use to the Air Ministry. The handling of
Brown
, moreover, gave us our first insight into the necessity of close liaison between intelligence and cryptography.
After the famous ‘Few’ had swept the skies of Britain clear by day, Hut 6 played its part in rendering the skies as hazardous by night. As most raids took place in the early evening, just after dark, the time factor was constantly on the thoughts of the cryptographer and a sense of urgency, such as was never felt again, permeated the whole Hut. For, never again, was the battle so close that the results of one’s work had an immediate personal interest, when the
difference
of an hour in breaking time might mean the difference between life and death for some inhabitants of this
embattled
island.
R. V. Jones was already convinced that there was a system of German wireless beams criss-crossing the UK to guide the
Luftwaffe
bombers onto their targets. These had been mentioned by captured German prisoners-of-war and a piece of paper salvaged from a Heinkel bomber shot down in March 1940 referred to ‘
Funkfeuer Knickebein
’, or in English ‘Radio Beacon Dog-Leg’. The word
Knickebein
recurred on a low-level coded message intercepted by Cheadle. Jones recalled getting a call from Professor Frederick ‘Bimbo’ Norman, the pre-war Professor of German at King’s College, London, and one of the Hut 3 reporters, in the early hours of the morning one day at the beginning of September 1940.
‘Two or three nights before the bombing of London started on 7 September, my sleep was interrupted by an event which
made more impression on my memory than any bomb ever did,’ Jones said.
The cryptographers had broken a new line of Enigma traffic. There was mention of beams, including one which said that the beam width was eight to ten seconds of arc, or an angle of one in twenty thousand, which would imply that the beam was no wider than twenty yards at two hundred miles. I asked Bletchley to put every possible effort into making further breaks into the new line of traffic. If only we could decode the Enigma messages in time, we could find where and when the German bombers were going to attack and so counter them by having fighters waiting and by having our jamming ready on the right frequencies. This would make great demands on the codebreakers, for the orders did not go out to the beam stations until the afternoon, giving only two or three hours to make the break, but for such a prize they strained every resource of human intelligence and endurance; and it was a great day, late in October, when they achieved this fantastic feat for the first time.
Despite the codebreakers’ frequent ability to break the
Brown
, providing ‘vital intelligence’ that allowed the RAF fighters to lie in wait for the German bombers, it was occasionally
impossible
. This was sadly the case with one of the most devastating bombing raids carried out by the Germans, against Coventry on 14 November 1940. Enigma had revealed that there was to be a major operation against the UK on that day and that it was codenamed
Moonlight Sonata
, but the only clue to what it might be was the vague mention of a codeword
Korn
(the German for corn). There was no indication as to what it meant but it later transpired that it was an alliterative code for Coventry which the Germans spelt with a K. On the day itself, the
Brown
Enigma could not be decyphered. The raid on Coventry destroyed 4,000 homes, three-quarters of the city’s industry and killed as many
as 600 people, injuring more than a thousand others. After the secret of the breaking of the Enigma cyphers emerged in the 1970s, a myth grew up that Churchill had insisted that the RAF should not attempt to stop the raid going ahead in order to prevent the Germans realising that Enigma had been broken. It was certainly the case that there was concern that the way in which the RAF fighters were waiting for the Germans and the air raid precautions put in place in the target areas might lead the Germans to suspect that Enigma was being broken but this played no role in the Coventry raids and the initial concerns over the effect on Enigma were not at any event raised until some time after the Coventry raid.
The simple truth is that the keys for that day were not broken until after the raid had taken place. Keith Batey, one of the Hut 6 codebreakers working on the
Brown
cypher, said he had
a clear recollection of our saddest failure: although messages in early November 1940 had given notice of a special
operation
codenamed
Mond[licht]
, we did not know more and to our dismay did not break any key for several days before 14 November: the result was the unhindered and disastrous bombing of Coventry. The missing keys were later broken and we could not explain the earlier failure.
A week after the Coventry raid, Bletchley Park itself was bombed. ‘On arriving at office this morning, found it had been bombed in the night,’ Malcolm Kennedy recorded in his diary.
Typists’ room and telephone exchange in our building blown to bits by a direct hit and the vicarage next door damaged by another bomb which landed in the garden. A third exploded in the road outside, while two more landed over at the Park, one of them bursting a bare half-dozen paces from Hut 4. By great good fortune there were no casualties. We, however, have had to give up our room to the typists and have been moved to
the room used by the South American Section who, in turn, have been transferred to the Park.
Gradually, there was more cooperation between the RAF
intelligence
and signals chiefs and Bletchley Park, who thanks to the reports from Cooper’s ‘Computors’ and the
Brown
Enigma were beginning to appreciate the value of the intelligence the codebreakers could provide. They set up a new RAF intercept site at Chicksands Priory in Bedfordshire, which took some of the burden of the Enigma traffic from the Army operators at Chatham, but it was not until early 1942, when the Bletchley Park Air Section challenged the very low Air Intelligence
assessments
of the number of
Luftwaffe
fighter aircraft – an
argument
borne out by Bomber Command’s lack of preparation for the German fighter defences it faced during the bombing of Germany – that it was finally allowed to issue its own daily reports to RAF customers on
Luftwaffe
command and control and tactics.