MI6

MI6, placed under the British foreign office and officially known as the Secret Intelligence Service from 1921, had the responsibility of gathering foreign intelligence relating to national security (see MI5 for definition). ‘C’, the chief of MI6, was also responsible for the government Code and Cypher School at Bletchley Park where the German ENIGMA and Geheimschreiber signals were decrypted and which produced the vital ULTRA intelligence.

While there is general agreement that intelligence had an important part in winning the Second World War, this verdict is associated in most minds with ULTRA, and the official history ( F. H. Hinsley et al., British Intelligence in the Second World War, 5 vols., London, 1979–91), by concentrating so heavily on this aspect, has put the verdict beyond appeal. This hardly does justice to the role of MI6, nor to the principle that the most reliable intelligence is nearly always that derived from the congruence of different sources. It should also be borne in mind that MI6 also provided the Special Liaison Units by which ULTRA was communicated to the military headquarters in the field. These units played a vital role in safeguarding ULTRA throughout the war.

The low rating of MI6 at the start of the war was directly due to neglect at the hands of the foreign office and treasury which did not understand that intelligence requires a long-term perspective and cannot be turned on, like a tap, when a crisis impends. This neglect, combined with the intractable problem that MI6 officers faced in trying to penetrate the defences of the totalitarian states of the USSR and Nazi Germany, resulted in a grave deficiency of strategic intelligence immediately before the war and during its early phase. When the purse-strings were at last released in 1938, the head of MI6, Admiral Hugh Sinclair (‘C’), made a start by building up his counter-espionage section and creating a new section (D) for sabotage and subversion. One of the new recruits into Section D was the traitor Guy Burgess; but in 1940 he was dismissed for incompetence.

Sinclair's death late in 1939 and his replacement by Stewart Menzies coincided with the abduction of two of his officers at Venlo. Their disclosures greatly contributed to the loss of the European networks, so that Menzies found himself virtually starting from scratch. His position was further weakened when Churchill came to power in May 1940, removed Section D from MI6 and incorporated it into SOE which came under ministry of economic warfare, not foreign office, supervision. The ensuing rivalry between MI6 and SOE for scarce resources, such as transmitters, light aircraft, and coastal craft, was probably unavoidable, but could have been mitigated if both organizations had been answerable to the same cabinet minister. Only in New York, where British Security Co-ordination was set up in August 1940, was there an effective merger of the activities of MI6, MI5, and SOE.

In September 1941 Section V recruited from SOE the traitor ‘Kim’ Philby, who later ran counter-espionage in the Iberian peninsula and Italy. Section V established a sound working relationship with MI5, especially in the joint exploitation of controlling Axis agents (see XX-committee). This exploitation was greatly helped when, in March 1940, the Abwehr's hand cipher was broken, later followed by its machine ciphers and those of the Sicherheitsdienst or SD (see RSHA). From October 1940 the Abwehr's signals were issued as the ISOS series and the SD's as the ISK series (the initials of the heads of the Bletchley Park sections which decrypted the signals: Intelligence Section, Oliver Strachey, and Intelligence Section, Knox). Later it became common for all German intelligence signals to be circulated as ISOS, regardless of origin or method of encipherment. Both ISOS and ISK were controlled by Section V.

The close collaboration between Section V and MI5 survived the contested transfer to the former in early 1941 of the Radio Security Service (RSS), which listened to German intelligence signals and for any illicit domestic transmissions; but Section V at first imposed a ban on the wider circulation of papers produced by the RSS analysis bureau. This problem was only overcome in the summer of 1943 when responsibility for the bureau was transferred from Section V to Section VIII.

Another effective adjunct to the strength of MI6 was the creation of a scientific section, in which the moving spirit was R. V. Jones. His incorporation in the MI6 air intelligence section, headed by Group-Captain F. W. Winterbotham, meant that links with the air ministry were particularly close and fruitful. Winter botham was also instrumental in developing photographic reconnaissance which was taken over by the RAF on the outbreak of war.

Initially, there was a tendency in Whitehall to impute to failure of intelligence-gathering errors and oversights that were more properly attributable to failure of assessment. Thus failure to foresee Hitler's invasion of Norway in April 1940 (see Norwegian campaign) and of the USSR in June 1941 (see BARBAROSSA) must be ascribed primarily to defective assessment of such intelligence—admittedly limited and sometimes contradictory—as MI6 was providing. But as the Joint Intelligence Committee (see UK, 8) acquired greater aptitude, this aspect of the problem came to be better understood.

During 1942, as the Allies began to move over to the offensive, the demand for tactical intelligence grew and here MI6 was able to play a more effective part. ‘C’ could rely on co-operation with the intelligence services of the Allied governments-in-exile, of which the Poles and the Czechs, who were permitted to maintain their own lines of communication to their intelligence networks, were the most effective.

The German occupation of Vichy France in November 1942 weakened the links established there; but the fact that such links persisted damaged co-operation with the Gaullist Bureau Central de Renseignements et d'action. Nevertheless, clandestine activity in France gained momentum and proved of special value along the Atlantic coast, where U-boats were based and German blockade runners and auxiliary cruisers found shelter (see also canoeists). No major landings in Europe could yet be contem plated, but MI6 gave essential help in planning cross-Channel raids, such as those against Dieppe and St Nazaire. Ship-watchers (see also Coast Watchers), mainly Norwegians, were also installed on the Norwegian coast, where German warships lay in wait for Arctic convoys, and reports from them enabled attacks to be launched against them by aircraft and midget submarines. Useful contacts with the German internal resistance (see Schwarze Kapelle) were also maintained in Sweden and Switzerland. But it was difficult to estimate the state of morale in Germany, just as it was the state of the economy. Agents (see spies) and informers could locate factories, but could not gauge output accurately.

Two areas in which agents' reports, supplemented by photographic reconnaissance, enabled heavy losses to be kept to a minimum were in the exposure of German radar defences and in the confirmation that the Germans were developing V-weapons of an unprecedented kind. As RAF Bomber Command intensified its strategic air offensive against Germany, it was of vital importance to locate and neutralize the defensive ring round the German heartland (see Kammhuber Line). The raid on Bruneval, facilitated by MI6 reports, was of special importance in discovering the complexity of these radar defences and in countering them (see electronic warfare). As regards V-weapons, agents' reports of activity at Peenemünde had begun to come in as early as November 1939, when the Oslo report mentioned it. Two years later it seemed increasingly likely that both missiles and rockets of some kind were being built and tested there. As evidence accumulated, much of it coming from conscripted non-German labour, ‘C’ successfully challenged the persistent scepticism of Lord Cherwell (see Lindemann), and in August 1943 major air raids at last took place. These critically delayed production and impelled transfer of research to Blizna, deep in Polish territory. On the French and Belgian coasts launching pads and storage sites for the V-1 were discovered; a single agent identified no fewer than 37. These discoveries, and the air attacks which followed them, averted an untold number of casualties in London and south-east England.

In the run-up to the Normandy landings in June 1944 (see OVERLORD) an agent stole the plans of the Atlantic Wall; others contributed sketches of 80 km. (50 mi.) of the coastline where the landings were to take place. Even after OVERLORD Section V still had work to do for it formed Special Counter-Intelligence Units which accompanied the armies to France and advanced with them into Belgium and the Netherlands. This was an important task, even though rumours of Nazi Werewolf packs proved exaggerated.

MI6, which had begun the war at a low pitch, ended it on a high note. Maj-General Strong was right when in his book Men of Intelligence (London, 1970) he described the latter years of the Second World War and the early post-war period as a kind of golden age for British Intelligence.

Robert Cecil