SIGINT successes and failures

a review by Paul Croxson


In 1917 Room 40, the Admiralty equivalent of Bletchley Park in the first World War intercepted a telegram which despite the opposition of President Woodrow Wilson led to the abandonment of neutrality and entry of the USA into the war. This was possibly the greatest sigint coup of all time.


This was the swansong of the mighty dreadnought battleship. Thirty five were engaged on the British side and twenty one on the German. It would have been a crushing victory if only the advantage of superior intelligence had not been dissipated by a faulty system. Room 40 still saw itself as a cryptographic bureau rather than an intelligence gathering centre. This battle is still considered to be a victory by both the Germans and the British.


Despite being warned by BP of exceptionally heavy traffic the Admiralty did not take this as presaging the invasion of Norway. This gravely affected the whole campaign. It meant that the Home Fleet was not in a position to strike at the enemy when at its most vulnerable. It led to the sinking of the aircraft carrier Glorious which was evacuating RAF fighter squadrons from Norway.


On 21 May 1940 Bletchley Park began what was to be its uninterrupted penetration of the principal Luftwaffe cipher which was to become the constant staple of Ultra throughout the war. Unfortunately this success came too late to save the battle for France. From then to the end of the war the main Luftwaffe ciphers were broken daily giving a gateway into not only the Luftwaffe but also the operations of the German army to the scientific secrets of current and projected weaponry.


During the Battle of Britain, Ultra’s eavesdropping on Goring’s scheme for using his 3-to-1 superiority in planes to “wipe the British Air Force from the sky” helped the RAF deploy and husband its forces until the Luftwaffe, crippled too, abandoned the attempt. Ultra showed that a big air effort was coming but could not help with dates.


Ultra did not provide precise details either about the number of barges being assembled or where it was planned they would land however it did reveal the disbanding of the staff specially constituted by Hitler to control the invasion. This gave the reassurance that the invasion would be off for at least a year. This information was described in those stressful days as “a strategic plum” although the authorities seemed curiously reluctant to accept this view and anti-invasion precautions – particularly naval – were maintained longer than were necessary.


The Blitz was an attempt to destroy British morale, industry, airfields and ports. A month before the Blitz began, BP broke a special GAF Enigma cipher which enabled information to be obtained which led to the development of counter- measures helping to abort or misdirect a number of German raids. It could not have saved Coventry.


Decoded Enigma messages in the spring of 1941 warned the British about German intentions against the Balkan states, first Greece and then – after the anti-German coup in Yugoslavia – against that country as well. Such intelligence, of course, was of extremely limited value due to the overwhelming forces that Hitler deployed in the region.


General Freyberg VC, a personal friend of Churchill, was better known for his bravery than his intellect. Freyberg was in possession of the most detailed plans that were ever likely to be made available to any commander. He misread an Ultra message believing it was advising that an invasion fleet was heading straight for the island and seemingly chose to ignore or misunderstand the precise information provided to him by Ultra on the air attack. In spite of specific warnings only eight guns had been allocated to the defence of Maleme airfield, others being put in place to defend against the expected sea invasion which never took place. Freyberg slavishly followed the order that the airfields should be left intact after the evacuation of the RAF. Following the defeat and evacuation many troops were lost as was much of Cunningham’s fleet en route  to Egypt. Three cruisers and six destroyers were sunk, two battleships, one aircraft carrier, two cruisers and a destroyer suffered such damage as would take months to repair. Over 2,000 officers and seamen were lost. Had Crete had been held the airstrips would have made a superb base for attacking the Ploesti oilfields. Frustrating for the intelligence community and disastrous for British forces Crete had however, whetted Churchill’s appetite for this “miracle” source.


Through spring 1941, the British had had little luck in solving the Kriegsmarine’s (NAVY) ciphers. But in mid-May 1941, they captured not only a German weather trawler with considerable material detailing settings for naval codes, but also a U- boat, U-110, with its cipher machine and all accompanying material. With these seizures, British intelligence gained the navy Enigma settings for the next two months. As a result, the British were able to break into U-boat message traffic at the end of May. Because German submarines were closely controlled from shore, and a massive amount of signalling went back and forth to coordinate movement of “wolfpacks” (groups of U-boats), the British gained invaluable information ranging from the number of U-boats available to tactical dispositions and patrol lines. Moreover, once they had two months’ experience reading the naval message traffic, British cryptologists continued breaking submarine transmissions for the next five months. The impact of this intelligence on the Battle of the Atlantic was immediate and crucial.

By 1943 the Allies were using Ultra, when available, in moving their convoys across the North Atlantic, so that the great formations of merchant shipping could avoid submarine patrol lines. In one particular case, decodings had picked up a heavy concentration of German submarines north of the Azores and so a major convoy of aviation fuel tankers from the refineries at Trinidad to the Mediterranean was rerouted to the south of the Azores. Unfortunately, because his escorts needed refueling and the weather was better north of those islands, the convoy commander disregarded his instructions, sailing north of the Azores, and ran smack into the U-boats. Only two tankers reached port.


In March 1941 Ultra revealed that the Germans had induced the Italians into positive action against the British convoys and this resulted in the overwhelming British victory at the Battle of Matapan which kept the Italian fleet at port for the best part of the war and gave the British command of the Mediterranean.


It is a myth that GC&CS were able to keep the War Office (MI) informed about every move that the Germans would make in North Africa. Far from providing advance information on German intentions to intervene in the Mediterranean, Sigint failed to provide evidence from the first GAF (Luftwaffe) key in the African theatre in 1941 and as a result awoke in February 1941 to find considerable German ground and air forces already established in Tripolitania. Sigint did however quickly provide evidence of what the German intentions were more often from traffic analysis rather than decryption. From then on sigint may be said NEVER to have failed to provide evidence of a major enemy strategic intention although that evidence was being disregarded as late as the Battle of Gazala in May 1942 or misinterpreted as late as the Ardennes offensive in December 1944 or the occupation of Hungary.

No German Army Enigma key became consistently vulnerable until spring 1942. German military low-grade material was not even being intercepted under GC&CS until the summer of 1942; its exploitation was left to the Middle East and when GC&CS eventually did begin to give a hand in winter 1942/3 it acted not as an intelligence producing centre but as a library and clearing house. Italian military high-grade systems defied cryptanalysis from the end of 1941, and the exploitation of low-grade material which was being undertaken solely in the Middle East produced less and less intelligence of operational value. Medium- grade Playfair (a method of hand-encipherment) traffic was also studied but produced little intelligence prior to the Normandy landings. Williams who advised Montgomery mentioned two occasions when cryptanalysis produced an operational dividend. In the end it appeared that in practice the criterion was not the grade of the system, but whether encipherment was machine or manual when it came to selection by GC&CS.

From the military section of GC&CS which was concerned with all army material not mechanically (i.e. non-Enigma) enciphered the War Office received practically no intelligence at all. High-grade Italian became indecipherable at the end of 1941 and the section seems hardly to have regarded the production of intelligence from field codes as part of its commitment. No wonder MI8 for so long preferred the “WTI” produced elsewhere other than GC&CS

The original resources for military intelligence in the Mediterranean were drawn from 2 W/T Company Sarafand, where it had been based since 1924 and supplemented during 1940 by cryptanalytic reinforcement from GCHQ, then known as GC&CS.

No 5 Intelligence School was the army component of the Interservice CBME (Combined Bureau Middle East) based in Heliopolis, Cairo. It was reinforced by drafts and field units and expanded considerably and a new School No. 7 Intelligence School was formed.

No longer needed, CBME was dissolved early in 1944, leaving No. 5 SIC (formerly 5 IS to serve Middle East and 7 SIC formerly 7 IS to serve in Italy.


It was Ultra and not General Montgomery’s much celebrated “intuition” that revealed when Rommel would strike at El Alamein, the turning point for the British in the North African desert war. The extent of the penetration of the German command structure by traffic analysis (not decryption) was so profound and so pervasive that it is clear that it changed not only the conduct but also the outcome of Allied European Operations in WWII. Most brilliant of ULTRA successes were against the German Afrika Korps and achieved locally. On occasion, according to folklore, the 8th Army HQ read Enigma telegrams before Rommel himself. The only evidence of this seems to be a message which Rommel asked to be repeated which had already been deciphered. GAF Enigma ciphers played a very significant role, helping the Allies to devastate the Axis supply convoys and gain a distinct edge over Rommel. It was the Allied knowledge of the German Air Force enigma ciphers that was of most use in North Africa, as the German Air Force was involved in most operations in the

Mediterranean and in the desert; its dispositions and movements could give indications as to the whereabouts of enemy units and activity whilst also helping plan the Allied air strategy. Montgomery particularly disliked the rather “ungentlemanly” form of warfare and therefore thought it not as important as it could have been. Intelligence still proved itself valuable on several occasions. He particularly disliked the fact that Churchill and others were as well informed as he about Rommel’s intentions. Ultra was said to “have taken the blindfolds off our eyes”.


Signal intercepts of information concerning the supply movements  from Sicily and southern Italy to North Africa resulted in decisive strikes on Italian convoys by Force K in Malta, Force H in Gibraltar and Force B in Alexandria, which in August 1942 at Alam Halfa forced Rommel to switch to the offensive when tactically he would not otherwise have done so. Ultra was not always successful! Preceding the battle of Gazala in North Africa in 1942, the Allies were misled entirely into thinking that Rommel had lost the best part of his armour and was planning to deploy defensively, when in fact, due to the fact that he had received new panzer tanks with face-hardened armour plating, he was being indecisive and eventually decided on offensive action with superior armoured forces


During the battles for control of the air over Sicily, Ultra proved equally beneficial. It enabled the Allies to take advantage of German fuel and ammunition shortages and to spot Axis dispositions on the airfields of Sicily and southern Italy.


As the D-Day landings approached in Normandy, Ultra was scrutinised for signs of a Nazi alert; there were none, and Operation Overlord’s surprise was complete. An enormous amount of information about the Atlantic sea wall was gathered from the interception and decryption of messages from the Japanese ambassador in Berlin to Tokyo. During the Allied breakout from the Cherbourg peninsula, came a “Hitlerian” command reflex that the Ultra team had learned to expect. Every time things went wrong, Hitler invariably took remote control, which was a bonus, since most of his signals went out on the air. This time Hitler’s frantic radio orders gave Eisenhower “the master plan straight from the Führer.” With the Nazis trapped at Falaise, Eisenhower sent General Patton plunging east toward Germany: “Without Ultra we might have had to meet the Russians on the Rhine instead of the Elbe, and they would have stayed put.”


In 1943 Luftwaffe message-traffic intercepts indicated – quite correctly – how seriously Allied air attacks were affecting the German air industry, prompting the U.S. Eighth Air Force’s commander to make a second great attack on the Schweinfurt ball bearing factories in October 1943. This proved disastrous for the Eighth Air Force crews who flew the missions. They lost sixty bombers and a further 122 were severely damaged out of the 291 that had set out.


In 1943, American pilots, armed with precise information from Ultra, shot down the Japanese Navy’s Pacific chief, Admiral Yamamoto, over the island of Bougainville,


Another substantial contribution of Ultra to Allied success was its use in conjunction with air-to-ground attacks. Ultra intercepts together with direction finding revealed the exact location of General Leo Geyr von Schweppenburg’s Panzer Group West headquarters. Obligingly, the Germans left their vehicles and radio equipment in the open. The subsequent air attack not only destroyed most of Panzer Group West’s communications equipment but also killed seventeen officers, including the chief of staff. The strike effectively eliminated the headquarters and robbed the Germans of the only army organisation they had in the West that was capable of handling large numbers of mobile divisions.


For rest and refit of panzer formations, HeeresgruppeBaker [Army Group B] ordered afternoon fourth [September 4] to remain in operation with battle-worthy elements: two panzer, one-six panzer [Second, Sixteenth Panzer Divisions], nine SS and one nought [Ninth, Tenth] SS panzer divisions, elements not operating to be transferred by AOK [controlling army] five for rest and refit in area Venloo- Arnhem-Hertogenbosch. This intelligence, via Ultra, along with a second confirmation on September 6, indicated that at the very time when the British- planned Operation Market Garden was moving forward, some of Germany’s best panzer divisions would be refitting in the town selected as the goal of the British First Airborne Division and the operation’s final objective on the Rhine–Arnhem. Putting this message together with intelligence that soon emerged from  the Dutch underground in Holland that SS panzer units were refitting in the neighbourhood of Arnhem, Allied commanders should have recognized that Operation Market Garden had little prospect of success. Unfortunately, they did not put these pieces together (or if they did, chose to ignore them), and officers  at the highest level at Field Marshal Sir Bernard L. Montgomery’s headquarters who had access to Ultra also failed to draw the correct conclusions.


An unfortunate result of the rush to publish, after the existence of Ultra became known to the public in the early 1970s, has been the appearance of a number of legends. One of the most persistent is the belief that Ultra gave no advance warning to Allied commanders in December 1944 that the Germans were about to launch a major thrust through the Ardennes. Admittedly, Hitler’s intuition suggested to him that German security had been compromised and led him to undertake a series of unprecedented measures to veil the Ardennes attack. Still, there were overt indications even in the high-level codes about German operational intentions. Ultra pointed to a number of other indicators. Sigint had identified two new wireless networks to the east of the Ardennes. These suggested that the Wehrmacht was moving supplies of ammunition and fuel into the region behind the Ardennes. Since the Germans were desperately low on such materiel, the allocations of resources could only portend major operations to come in the Ardennes. Unfortunately, the mood in the higher Allied headquarters and in intelligence circles was euphoric – the war was almost over and the Germans could not possibly launch an offensive. They were wrong!


The ability to read messages was not the most significant contribution that Ultra made. It was the constant and thorough delineation of the German Order of Battle.


The Anglo–American solution of the Venona one-time pad ciphers used by the KGB during World War II, led to the uncovering of several spies both in the UK and in the USA. The project was a long running and highly secret collaboration that involved the cryptanalysis of messages sent by several intelligence agencies of the Soviet Union, mostly during World War II. Venona would be an important source of information for the Western powers on Soviet intelligence activity behind many famous events such as the Manhattan Project (building the atom bomb), the Rosenberg spying case and the defections of Donald Maclean and Guy Burgess.


The Cuban Missile Crisis of 1962 was a major strategic intelligence failure. It provided no warning of the presence of Soviet nuclear-armed intermediate- and medium-range ballistic missiles in Cuba prior to their discovery by U-2 reconnaissance aircraft.


Ten days before the Soviet Union invaded Afghanistan on 28 December 1979, sigint provided “specific warning” of the invasion.

PWC, October 14