Ralph Bennett’s first book on intelligence in the Second World War – Ultra in the West – dealt with the Normandy invasion and the campaign in North-West Europe. This volume appears later, in what he calls ‘an unnatural order’, because the material on which both are based was released to the public records without regard for chronological sequence. The book loses nothing in interest and value on this account: how could it, when the basic material is the signals which conveyed to the Allied commands the product of the decryption of the Axis high-grade cyphers? And when the author was among those who scrutinised the decrypts and composed the signals?
In some ways, indeed, the book is more interesting than Ultra in the West. As Mr Bennett says, the experience and the depth of knowledge which subsequently created a well-oiled machine for handling the complex processes of decrypting, translating, assessing, disseminating and using Ultra did not exist when Germany’s intervention set the Mediterranean ablaze in the spring of 1941. It was in the Mediterranean theatre that in relation to campaigns on land and sea-borne assaults, though not in the war against the U-boats and the German Air Force, the experience and the knowledge were built up. In the course of analysing the contribution made by the Ultra intelligence to the Mediterranean operations he is thus able to give an added dimension to the account by emphasising the steps by which, learning from their oversights and reflecting on their triumphs, the Allied intelligence authorities acquired their formidable efficiency.
Mr Bennett places the completion of the learning curve at the summer of 1942, and adds that this coincided with the point at which the Allied operational authorities at last deployed the levels of relative force and resources which were necessary before they could take advantage of the intelligence at their disposal. These judgments are, in general, correct. But not all of the arguments on which they rest are equally sound. Mr Bennett states that ‘the supreme importance of Ultra’ was only gradually appreciated and that it ‘had not yet been fully realised in 1941’. In fact, the supreme importance of Ultra was fully recognised before any of it became available. He supports the statement by claiming that, for some time after it became available, few if any of the recipients were told the truth about the source: they were asked to believe that the intelligence emanated from an omniscient agent, with the result that ‘generals brought up to distrust all agents’ reports paid little heed to it. In fact, this cover device was adopted hastily because no indoctrination procedure had been established in time for the campaign in Norway and the battle of France, Ultra having then come on stream unexpectedly: but thereafter the indoctrination of all Ultra recipients, with a few possible exceptions which may have included General Freyberg in Crete, included, as the word implies, a full explanation of the nature of the beast. If the cover device still continued in use for some time for the dissemination of Ultra, it did so chiefly for the purposes of security in the big Whitehall departments, where indoctrinated sections worked cheek by jowl with sections which had not been indoctrinated. The Admiralty never used the fiction, preferring other means of achieving security. Winston Churchill, on the other hand, was enamoured of it, with the result that references to the agent Boniface cropped up in his telegrams and letters till the end of the war.
What limited the value of Ultra in North Africa before 1942 was not the cover device – which, however amateurish it was, and was soon seen to be, was itself a tribute to the enormous importance that was always attached to the intelligence – but the scarcity of decrypts from the German Army, as distinct from the German Air Force and the Italian shipping authorities. Mr Bennett does not fail to make this point clear. But he does not sufficiently explore its bearing on the argument that the value of Ultra depended on the availability of adequate force at the disposal of its recipients. The relationship was more complex than he suggests. In the summer of 1942, when Auchinleck’s forces were inferior to Rommel’s, a thin trickle of Ultra was crucial in enabling him to keep Rommel out of Cairo. By the autumn the trickle had become a powerful stream: but Ultra had little influence on the outcome of the second battle of Alamein because Montgomery’s forces were distinctly superior to Rommel’s.
Both before and after that battle, and in other theatres as well as the Mediterranean, the outcome of other encounters amply illustrated the variability of this relationship between the amount of intelligence and the scale of force available. In some situations there was a steady supply of Ultra, as there was about Germany’s descent on the Balkans and her occupation forces in Yugoslavia, but no Allied commands which could make use of it. In other situations, as was often the case during the Italian campaign, the Allied commands deployed substantial forces but derived little operational advantage from an even larger supply of Ultra. But in Italy, as in North Africa, there were also situations in which, while little Ultra was forthcoming in time, that little was decisive, as at Anzio.
Mr Bennett brings out these variations with force and clarity in his detailed chapters, and all the more so because he focuses attention on the distinction between the operational or tactical value of Ultra and, on the other hand, the strategic advantage the Allies derived from it. This advantage was, as he shows, of particular value to them in shaping and pacing their conduct of the Italian campaign, coming as it did from the full knowledge Ultra provided of the deployment and scale of the enemy’s resources, and from the frequent insights it gave into his plans and intentions.
Ultra had not, earlier, been put to such good use in the planning and the waging of the campaign in Tunisia. Mr Bennett’s discussion of this campaign is salutary in that it demonstrates how far the course of battles is affected by other factors besides intelligence. In relation to the influence exercised by intelligence, however, it is in one respect inconclusive. It shows that, after all, opportunities were still being lost through inexperience and unpreparedness after the summer of 1942. It shows, as well, that lapses also occurred of the kind that any intelligence organisation, however efficient, will commit from time to time, as was to be the case, however occasionally, down to the end of the war. But the extent to which the Allied setbacks, as in the battle of Kasserine, were due to inexperience or to error, and the extent to which the errors were understandable or unforgivable – such questions, which chiefly arise in Mr Bennett’s account of the Tunisian fighting, but which also arise elsewhere, as in his discussion of the Allied failure to interrupt the Axis evacuation of Sicily, are not always settled by his comments on them. Some of them will probably, and perhaps unavoidably, always remain open to debate.