About 18 months ago, /u/saddetective87 asked this question about British Naval Intelligence during WWII. Unfortunately, I was busy at the time, and never quite got around to answering it. It's gnawed away at me, though, and so this is a (very late) answer to that question.

Room 39: British Naval Intelligence in WWII

Naval intelligence is the name given to information gathering, spying, and reconnaissance for naval means, as well as for the processes by which the data so gathered are analysed and disseminated. In the Royal Navy, this was the preserve of the Naval Intelligence Division (NID), also known as Room 39, after the room it occupied in the Admiralty. Room 39 was founded in 1887, and was one of the Admiralty's larger departments; in June 1939, it employed 24 officers and 42 civilians. Five years later, it employed 291 officers. For the first part of WWII, NID was the preserve of Rear Admiral John Godfrey, who implemented significant reforms. However, he had a poor relationship with his political superiors, leading to his removal in 1942. He was replaced with Captain Edmund Rushbrooke, who remained in command for the rest of the war. NID recruited from both skilled civilians and from naval officers. Some of its most famous officers had been civilians up to the start of the war - Godfrey's personal assistant, Ian Fleming, had been a journalist before the war, while Ewen Montague, who came up with the idea of Operation Mincemeat, was a barrister in civilian life.

Naval intelligence can be divided up into three main areas: technical, strategic, and tactical. Or, put simply, what the enemy can do, what the enemy wants to do, and what the enemy is doing. A great variety of techniques can be used to gather such information. While the Enigma decrypts are the most famous source of intelligence used by the RN, seventeen different categories of source were used. This post will give an overview of these sources, as well as a look at NID's activities in the pre-war period.

NID before the war

For NID, peacetime intelligence was very different from wartime intelligence. Firstly, NID was more concerned with technical intelligence in the run-up to the war, to determine whether or not Germany, Italy and Japan were keeping to the terms of the naval treaties of the 1920s and 1930s. Secondly, a wider variety of intelligence techniques could be used. Communication channels between countries were more open, and security precautions were lower, allowing for greater use of espionage. Port visits and other ceremonial functions gave chances for intelligence gathering.

In peacetime, the naval attache was one of the more significant sources of intelligence. They visited ports, dockyards and ships, they ran agents, and they maintained a close relationship with naval officers of the power they were in. Naval attaches received special training from NID before taking up their position, teaching them how to recognise and gather good intelligence. They were attached to the British embassy in the country in which they were based, and ran their operations from there. The naval attache in Berlin was supposed to have priviliged access to Admiral Raeder, head of the Kriegsmarine, though in practice this was limited. More useful were the close relationships they developed with naval officers and engineering firms. In the 1920s, the naval attache in Rome was told, by an Italian engineer, that the new Italian heavy cruisers were 1000 tons over the limit. In the 1930s, the naval attache in Berlin was able to use information gathered from engineering firms and naval officers to contradict SIS on German intents to buiild submarines.

With lighter security precautions, the British could also run spies within other countries. These were controlled by SIS (better known as MI6), but relevant information was passed to NID. In Germany and Holland, an engineer named Otto Kruger was a British spy. He was an engineer, working for the Dutch company Ingenieurskantoor voor Scheepbouw, a German front company for submarine experimentation. He later became a consulting engineer on the German submarine program at Kiel. From there, he gave the British a considerable amount of information, including information on German plans for increasing submarine production in wartime. Other agents included well-placed agents in Washington and Tokyo; the former gave information on American aviation developments, the latter on Japanese torpedoes.

A major source of low-grade information were official communiques and newspaper reports. The NID subscribed to all major newspapers, as well as to the local newspapers in major ports. While these gave little in-depth information, a lot could be gleaned from them - for example, if a shipyard was hiring large amounts of men, it was clear that it was embarking on a major building program. An NID officer stated 'The most valuable information is seldom secret. The difficulty is that people seldom realise its value'.

Finally, visits by foreign ships to British ports (and vice versa) gave opportunities for intelligence gathering. One of the bigger treasures of NID in the pre-war period was a highly detailed photograph of the German cruiser Deutschland taken through the scuttles of the netlayer Guardian when the former was visiting Gibraltar. This allowed the British to reassess their estimates of the displacement of the Deutschland class. A few months later, she was damaged by Republican Spanish bombers, and returned to Gibraltar for initial repairs; observations of her here gave the British information about her armour protection. In 1936, the Italian cruiser Gorizia was forced into Gibraltar after suffering heavy damage in a storm. She was repaired in the British dockyard there, allowing British engineers to measure her dimensions, her armament and protection, and to get limited access to her plans. When British ships visited foreign ports, the officers were given a thorough questionnaire by NID, asking in-depth questions about what they saw. British officers were very happy to serve in this way, and were enthusiastic about gathering information.

NID during the war

As mentioned above, NID used seventeen general sources of intelligence during the war. These were further subdivided by type, and graded individually, to quantify how reliable they were. Each piece of intelligence was given an alphanumeric code, from A1 to D5. This grading relied on an assessment of the source, its provenance, and how well it matched other available intelligence. The letter gave the reliability of the source, while the number referred to how likely it was to be true. Somewhat counter-intuitively, photographic intelligence was not always graded A1, as it was recognised that photos relied strongly on interpretation; nor could they reveal decoys or logistical failures.

Signals intelligence

Signals intelligence, or SIGINT, refers to intelligence gathered by reading or analysing intercepted messages, especially radio messages. It was one of the most significant sources of information for the RN. As well as decrypts of messages, other techniques such as traffic analysis or direction finding could be used to obtain intelligence. The British ran a radio interception service, the 'Y' service, which was able to intercept most messages sent. They were then passed on to the rest of the intelligence services for analysis.

Traffic analysis was the simplest form of SIGINT. It relies on recognising patterns in intercepted signals, whether or not they were decrypted. A simple example would be that a sudden increase in signals in the North Atlantic would suggest that a convoy had been sighted and was about to be attacked. German U-boats tended to make a number of routine signals that could be used to track their activities, with the 'E-bar' and 'B-bar' signals being most significant. The B-bar signal tended to be sent by submarines that were outbound from their home base, and were sent as attack signals. E-bar signals were sent by submarines on their way home, to give their time of arrival. By counting the number of these signals received, NID could get a good count of the number of submarines in the North Atlantic. Other forms of traffic analysis could suggest the movement of heavy units or the establishment of new flotillas. Analysing the way the signal travelled could also give information - for example, distinguishing between different ways signals propagated through the atmosphere could give the range to the transmitter, while certain forms of interference could show that the aerial was wet, and thus that the U-boat had just surfaced.

Another way information could be obtained from signals without decrypting them was through High Frequency Direction Finding (HF/DF), known colloquially as Huff-Duff. This was a method for finding the bearing to a radio transmitter. The Germans used HF radio to communicate between U-boats and shore stations. They believed that HF direction finding equipment would be too large to fit on a ship, and too inaccurate at long ranges from shore stations. However, the British and Polish developed small HF/DF sets, and they were rapidly fitted to many convoy escorts. HF/DF allowed escorts to track and find U-boats that were sending messages. It was highly effective, and got more effective as more ships were equipped with HF/DF aerials.

Week 20

 

As things are moving forward with talks about the dissolution of the Austro-Hungarian Empire, principle of nationalities and irredentism; despite the main focus being on the Italian side of things, I though better to include a brief picture of the Yugoslav situation. At the same time, that's by itself a complex matter and what literature I could find has proven quite elusive on the matter.

Therefore, if you feel something is worth correcting or if you have suggestions for further reading that may help clarify some points, please let me know. It's still a rather obscure subject in Italian literature.

 

On March 7^th the Italian representative Andrea Torre (Head of the Committee for Cooperation with Oppressed Nationalities), who had previously obtained the informal approval of Prime Minister V.E. Orlando, signed an agreement with the Yugoslavian representative A. Trumbic, serving as President of the Yugoslav Committee. The two men had met in London (under the good offices of the British Committee of R.W. Seton-Watson, W. Steed and A. Evans) together with a few others. For Italy the contingent included senator Vittorio Scialoja and publicist Vittorio Amendola. Despite the presence of the President of the Fascio Parlamentare di Difesa Nazionale, Scialoja, the initiative was positioned on the left of the interventionist block, with smaller groups such as the associations “Dante Alighieri” and “Trento e Trieste”. The purpose: finding a tentative agreement on a platform that included the establishment of a Yugoslav nation in the Balkans after the dissolution of the Austro-Hungarian Empire. The Committees acknowledged that the Austrian Empire was the key obstacle to the liberation of the Adriatic Sea and that both Italy and the Yugoslav peoples had their best interests in upholding the principle of nationalities. The territorial issues between Italy and Yugoslavia were to be settled “amicably” on the “basis of the principle of nationality and the rights of the peoples to self-determination […] in such a way not to hurt any of the vital interests of the two nations, that would have been defined at the time of the peace”.

The agreement – a preliminary to the Congress of Rome to take place in four weeks – was the result of the progressive realization among the allies that the re-organization of the post war Balkan region could no longer wait. It was also a clear example of unequal pact, where one part was by then acting under the investiture of the “official Yugoslavian Government” (since the Corfu agreement of the previous year) and the other was not much more than an informal diplomatic mission.

By early 1918 the internal situation of the Austro-Hungarian Empire had reached a point of dissolution of the complex network of relations and balancing powers that went beyond any possibility of repair and probably the establishment's own understanding of the crisis. The brief parenthesis of mutual acceptance that had appeared to follow the introduction of universal suffrage in 1907, in the wake of the promised “federative centralization” of Archduke Franz Ferdinand, had ended under the common disillusionment brought by the war among the popular classes and the peasantry – that more than anyone else had been the traditional basis of support of the multi-ethnic Empire.

 

Now, the situation gets more complex if one looks in detail at the concept of Yugoslavian independence; as anybody who attempts to define a “Yugoslav” can certainly see, and without any intention to touch on a loaded topic (that is not anyways my main focus), there was not in 1918 one Yugoslav nationality but a pattern of authorities, nations and nationalities of the Balkan Region that to various degrees accepted the idea of being part of a broader cultural identity. At the beginning of the War, one independent Serbian state existed, with an official government that was – by 1918 – in exile. A province, that of Bosnia-Herzegovina, had been annexed by the Austrians ten years earlier, another, that of Croatia (without the Dalmatian coast, which fell under the Austrian Crown and without Fiume, port city of the Hungarian Kingdom and common hub for meetings of patriots and conspirators of various kind) held some semblance of autonomy under the Hungarian Crown; south to the Albanian border, where Albania “sort of” existed under allied patronage and Austrian partial recognition, another province of Montenegro where substantial Muslim minorities existed; overlapping a bit with the historical region of Macedonia, claimed by Bulgarians and Greek alike and partitioned at the time of the two Balkan Wars.

Those “unofficial” oppressed nations had for obvious reasons no clearly defined representatives or governments (no free elections had been held in Austria and those representatives who choose to act against the Empire did so under penalty of death); which made diplomatic talks much more delicate and unsure as it was often difficult to establish how much actual weight was there beyond the words, with the Serbian Government often serving as a necessary (but interested) intermediate between the exiled leaders and the allies. Also, the purpose and intentions of those semi-official representatives were not necessarily unitary, and different nations may have held different and conflicting goals in terms of their own internal borders: the concept of a Serbian nation, extending over the entire region was especially problematic, more so now that the Russians – who in fact may have looked to the project with some concern themselves – appeared out of the picture. And for the very natural reason that Croats, Macedonians, Albanians, Greeks, Bulgarians, Bosnians, Christians, Orthodoxes, Muslims, saw and accepted in the principle of nationalities also the recognition of the right to their own independence.

This internal dialectic made difficult to find a compromise based on territorial concessions: one single Serbian led state could be created through the sacrifice of border lands that were in fact mostly Croat and Slovenian. The distinction between a minimal program (annexation of Bosnia, Montenegro and Macedonia with portions of the coast) and a maximum program (all of the actual Yugoslavia plus something) was a key element of Serbian Prime Minister N. Pasic's political action.

A second point of conflict came with the issue of whether the new Yugoslav state was going to be a continuation of the Kingdom of Serbia (in a way similar to how Italy had been united as a continuation of the Kingdom of Sardinia) or rather a new union of the Kingdoms of Croatia [there was in fact no Kingdom of Croatia and Croatia was a “special” province of the Kingdom of Hungary – despite the desires of the Croatians that had, like the Czechs before, offered the Crown to the Emperor, hoping to turn the “duality” system of 1867 into a federation of Kingdoms] and Serbia. If Serbia considered those lands as annexations, than they may very well be split with the populations relocating according to their own ethnicity – an eventuality much feared by the Croats who felt that the realistic consequence of such an event would have been a form of “denationalization” (splitting the Croatian lands among Italy and Serbia for instance would have forced the Croats of the coast to move south, thus leaving a more “Italian” region and indirectly destroying the national core of Croatia). To prevent this, the main focus of A. Trumbic political action within the Committee was to seek allied recognition of the independent Nation of the Croats, Slovens and Serbs, that would then merge with the Kingdom of Serbia. This was something that Italy had a much harder time supporting, than the simple idea of an expansion of the Kingdom of Serbia. The issue of defining the hopes and ambitions of the nationalities living under Austrian sovereignty in a clear, official and practical manner, would take up a large portion of the political activity of the various exile.