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Seventy Years Ago This Month at Bletchley ParkOctober 1940Britain Can Take It!With the failure of the Luftwaffe to break the back of the RAF, on the 12th October Hitler abandons the plans for the invasion of the UK, at least until the spring, but gives Goring the chance to demonstrate how he can bring the British to their knees by a continuous air assault. During the Battle of Britain from July until October 1940 the RAF have lost some 915 aircraft, but the Germans have lost 1733. The British front line strength has somewhat increased, while the Luftwaffe has significantly declined. But when Hitler meets Mussolini on 4th October he tells him “The war is won! The rest is only a matter of time” Now the question is how will the British stand up to seemingly endless night raids? Despite their navigation “beams” the bombing, though directed at rail centres, docks, factories and government buildings, was inaccurate so that there was much destruction of residential property. High casualties resulted, but there was little disruption of production. To everybody’s surprise morale actually strengthened; Britain could take it! The “Blitz”. The last major day-light raid on London, until the V weapons, took place on Sunday 15th September. More than 200 German bombers set out for London and 158 reached it, but that day they lost 34 bombers with a further 20 more damaged, a loss rate of 25%. Thereafter they switched to night bombing, the first major daylight raid on London having already taken place on 7th September. During October the raids were largely directed against London, and on the evening of 15th October 400 bombers attacked London. During the 8 months of the first “Blitz” there were raids on London on 71 occasions, and it was the primary target on 19 occasions; some 19,000 tons of bombs fell on the Greater London area. Sixteen of the major cities and ports of the UK suffered from nights of assault throughout the campaign and at least four of them suffered 6 or more attacks. The first Blitz lasted until 16th May 1941 when the Luftwaffe drew back to build up for the coming invasion of Russia, though the bombing of Britain was to be resumed in 1942. Overall the Luftwaffe dropped some 35,000 tons of bombs on the country in 1940/41 for the loss of 650 German aircraft. (However, to set this in perspective, one has to remember the RAF alone dropped over 50 times as many tons of bombs on Germany during the course of the war losing some 12,000 bombers and 55,000 aircrew). Intelligence during the Blitz. During the second half of September and throughout October the Intelligence Service obtains many indications that “Sealion”, the invasion, has been postponed until next spring. In fact on the 12th October Hitler has made the decision to put off the invasion, giving top priority to the planning of the invasion of Russia. But he has ordered a deception campaign about the invasion of Britain to be mounted to screen his plans for the attack on Russia. It is not until the last day of October that the Cabinet Defence Committee finally accepts that the threat has passed for this year. Now the Intelligence focus turns to the Blitz and to the Axis threat to the Balkans and in the Middle East, where BP starts to make a valuable input. As the war becomes static the Germans are able to use landlines for more of their traffic. But still a great deal of information is sent by radio; every day Bletchley Park is reading the Red Enigma key, the main general purpose Luftwaffe key, and almost every day reads the Brown key of the Luftwaffe regiment based in Brittany that operates the navigational beams used by their bombers. And BP has broken many of the Luftwaffe tactical codes and cyphers, such as those used by their bombers, and these are read regularly at the main RAF interception station at Cheadle. They are able to identify from their call-signs the squadron (“stallen”) and group (“gruppe”) to which each bomber belongs, so giving direct information on the numbers and organisation involved. (This does not stop the Whitehall Air Intelligence organisation from continuing to grossly over-estimate the numbers involved, despite the best efforts of BP and Churchill’s scientific guru, Prof Lindemann, to correct them). So the British Intelligence Service obtains in advance a considerable amount of information about the German plans for their air raids. On 18th October Air Intelligence warns that the Germans are planning more major night raids, using as many as 600 bombers. But the information is sometimes received too late to be of operational use, and the names of the German targets are given in a book-code. It takes time to accumulate the interpretation of these place names. The RAF has learnt to detect and jam (or bend) the navigational beams themselves, but the Germans are using several navigation systems and the, at first ineffective, jammers of the X-Gerät system were not operational until November 1940. Diplomatic Rebuffs for Hitler. Despite his apparently overwhelmingly dominant position, Hitler found allies to his West were hard to win over. On 23rd October he meets General Franco at the Spanish border with France, but fails to persuade him formally to join the Axis countries, or even to allow German troops through Spain to attack Gibraltar. Then he meets General Pétain, but Pétain also refuses an alliance, even though it would mean the return to France of a million and a half French prisoners-of-war. And on 27th October General de Gaulle makes the “Bazzaville Declaration”, inviting all French overseas possessions to join his “Free French”. On 28th October Mussolini invades Greece from Albania without warning Hitler, who had not troubled to inform Mussolini before he sent his troops into Rumania and its all-important oil-fields on 7th October. Hitler considers it was a grave mistake to move into Greece, as Italy should concentrate on its advance on Egypt, which is stalled by supply difficulties at Sidi Barrani. Far away across the Atlantic President Roosevelt orders selective military training, with 16 million US citizens registering on 16th October. And on 24th October the US signs a secret agreement to equip ten British divisions. Dissention within the UK Intelligence World. On 27th September 1940 Churchill’s security officer, had written to “C”: “I have been personally directed by the Prime Minister to inform you that he wishes you to send him daily all the Enigma messages”. (In a postscript that shows how well he knew the irregular habits of his boss, Desmond Morton had asked C to institute a check that all the documents were returned as it would be impossible to check at No.10 that all had been accounted for). It would, of course, have been quite impractical to follow this instruction to the letter, but it is known that Churchill was sent a box every day containing a selection of up to 20 decrypts together with a summary prepared by GC&CS. Though Churchill made good use of the information he obtained so promptly, both with the authorities in Whitehall and the commanders in the field, it is said that he was not always correct in the deductions that he drew from this singular stream of information. This use of their work was clearly a vote-of-confidence in BP, but the bypassing of the “correct channels” did not endear the BP staff to the Whitehall Intelligence machine. It has to be remembered that at this time the function of BP was cryptography; to the extent that when they extracted Intelligence information from the material they decrypted it was supposed to be solely to assist them in their code-breaking work. And indeed the Naval Section at BP was punctilious in sending to the Admiralty Intelligence Sections all the messages that they broke in full, but in translation. However, the assembly of such brain-power at BP was already proving a powerful tool for interpreting the Intelligence that they received, even though they were not in possession of information from other sources such as agents’ reports, photo-recce, prisoner debriefings, etc. The size of the organisation at Bletchley Park had increased four-fold since they first arrived in August 1939, and that growth had been in response to the needs and opportunities thrown up. So the organisation of BP at this time “remained a loose collection of groups rather than forming a single, tidy organisation” in the words of the Official Historian, Harry Hinsley. “Many of the new recruits had been drawn from the universities and similar backgrounds. Professors, lecturers and undergraduates, chess-masters and experts from the principal museums, barristers and antiquarian booksellers, some of them in uniform and some civilians on the books of the Foreign Office or the Service ministries – such for the most part were the individuals who inaugurated and manned the various cells which sprung up within or alongside the original sections. They contributed by their variety and individuality to the lack of uniformity. There is also no doubt that they thrived on it, as they did on the absence at GC&CS of any emphasis on rank or insistence on hierarchy”. But in October 1940 the young Harry Hinsley, working in Hut 4 at BP, had written of his colleagues in the Admiralty “I suspect that another reason for their inadequacy is incapacity, pure and simple”. Inevitably the Whitehall Intelligence Directorates felt threatened by this collection of unorthodox and “undisciplined” wartime staff, and it is hardly surprising if the two bodies found themselves unable to agree on how to integrate their joint efforts and on how to strengthen the higher administration of BP without destroying the conditions of creative anarchy that existed To make matters worse, by this time in the autumn of 1940 the work of BP had been much more beneficial for the Air Ministry than it had been for the Admiralty or the War Office. Rather surprisingly, after a difficult start, relations between the Admiralty, in particular it’s Operations Intelligence Centre, and BP developed very well, with them now relying on BP to do Traffic Analysis work as well as cryptography. Then in March 1941 they appointed a naval Captain to be both assistant director of the OIC and responsible for the co-ordination of the actions taken on the material emanating from BP. Discord never again flared up between the OIC and BP’s Naval Section under Frank Birch. The Air Ministry was getting a full stream of information from BP and, as a result of the work at BP, through their Cheadle centre. They had come increasingly to co-operate with BP and indeed to rely on them for the extraction of Intelligence from the many decrypts. Yet there was continuing disquiet in some of the Air Intelligence Directorates at the way that BP was taking over responsibility for all Signals Intelligence, even its interpretation. Even worse, the War Office who had, so far, gained very little from the work of BP, was convinced that BP was not the body to extract the Intelligence of interest to the Army. They resented the direct links that had built up between parts of BP and the appropriate War Office departments. Conflict wore on for many months, only gradually fading away as the quality of the Intelligence deriving from BP’s decrypts of direct value to the Army improved, as their number became a flood. Dissention within BP. Nor did harmony and light always reign inside BP, but at least internally among the senior staff the conflict is enlivened by the wonderful language in which it is couched, and by the colourful personalities. In the autumn of 1940 priority for the use of the two Turing bombes is being given to Hut 6 and its work on breaking the Luftwaffe keys. Frank Birch is complaining bitterly to the Director that his naval Enigma team in Hut 8 has “not produced any results at all so far… 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 dither between theory and cribbing”, though at the very same time he is complaining that they are not receiving the priority in bombe time that he considers they deserve. And as usual, the successful, if aging, head of the Research Section, Dilly Knox, is complaining in outspoken language to the Director, this time that in handling the decrypts from his work on the breaking of the Italian naval Enigma, he has been “tricked” into agreeing to pass the Intelligence extraction and distribution over to Wilfred Clarke, head of the BP Italian Naval Section. Dilly felt this did not befit his status and reputation as a scholar. Frank is soon to have good reason to revise his opinion of his remarkable cryptographers but Dilly never ceases to bind to his old friend. The Bletchley Park Trust welcomes the preparation of these notes, but the authors are responsible for the statements and the views expressed. |
