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History of the Second World War: British Intelligence in the Second World War #1
British Intelligence in the Second World War: Its Influence on Strategy and Operations, Volume I
British Intelligence in the Second World War provides the only reliable account yet published--or ever likely to be published--of the part played by British intelligence in allied strategy and operations in the Second World War. No such account could have been written without the unrestricted access which was afforded to Professor Hinsley and his colleagues to the full range of British government intelligence records and to political and military archives of the war and before.
- GenresWorld War IIHistory
601 pages, Hardcover
First published June 11, 1979
About the author
F.H. Hinsley
23 books8 followersSir Francis Harry Hinsley OBE, was an English historian and cryptanalyst. He worked at Bletchley Park during the Second World War and wrote widely on the history of international relations and British Intelligence during the Second World War. He was known as Harry Hinsley.
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Displaying 1 - 3 of 3 reviews
June 13, 2026
In 1952, the first book in the United Kingdom’s official history of the Second World War, T. K. Derry’s The Campaign in Norway was published. In the 27 years that followed, thirty-eight more volumes were produced that recounted British military operations during the conflict across theaters in Europe, North Africa, and Asia, as well as the development of a coordinated strategy for them. Based on extensive access to government archives, they provide detailed accounts of their representative topics, and continue to serve decades later as foundational studies of their subjects.
Yet in all of these volumes, something was missing. For all of their thoroughness, one aspect of the war was mostly absent from the narrative – the impact of intelligence operations on decision-making. Though there were occasional references to the information obtained, these were deliberately vague and mentioned in passing only. The reason for this was simple: in the immediate aftermath of the war, many of the means of obtaining it were still classified and thus could not be discussed officially. With the reduction in the 1960s of the closure period for official records from fifty years to thirty, however, much of the material about these activities became public in the early 1970s, making possible at last the incorporation of intelligence activities into the official account.
The task of writing intelligence activities into the history of the war was assigned to a team led by Francis Harry Hinsley, a historian familiar with wartime intelligence work from his time as a cryptanalyst at Bletchley Park. What he and his co-authors provide, however, is not an insiders’ account of code-breaking or novel-esque narratives of secret agents conducting espionage inside Nazi-occupied Europe, but an analysis of what information was collected and the role it played in shaping the decisions made by British political and military leaders. It is one that demonstrates just how wide the gap is between fiction and fact in the reputation enjoyed by British intelligence services today, and how much work they had to do make an effective contribution to Britain’s wartime efforts.
This work was necessary given the general neglect of intelligence during the interwar era. Suffering from the inevitable budgetary reductions in the aftermath of the First World War, both the military intelligence branches and the civilian-led Secret Intelligence Service (SIS) and Government Code and Cypher School (GC & CS) were parsimoniously funded until practically the eve of the war. This was exacerbated by a lack of coordination, as the various services guarded jealously their prerogatives from encroachment. This inhibited the collection and collation of information as British officials attempted to assess the capabilities of a resurgent Germany in the 1930s and their readiness for war, which contributed to many errors in judgment.
Offsetting this to some degree was the intelligence obtained or inherited from Britain’s allies, such as the Polish efforts to crack Enigma and the Czech intelligence asset Paul Thümmel, whose “A-54” designation recurs throughout the text. Yet for the first several months of the war, there was little in the way of inter-departmental coordination, as the intelligence branches struggled with adjusting to the new circumstances of the war. This contributed to the Germans’ success in obtaining surprise with their invasion of Norway, as what information was available was not pieced together in time for the Allies to prepare. While such success was not possible for German plans for Western Europe, the details of it were successfully concealed. Yet for all of their failures in the spring of 1940 and the disasters to which those failures contributed, British intelligence was adapting to the demands of war, learning not just how to acquire better intelligence, but to use it more effectively and in a timely manner.
Such adjustments could not come soon enough, as by the summer of 1940 British intelligence was facing their most urgent problem of the war. With the threat of invasion looming, the pressure to provide both details about the preparations and, most importantly, the date of its launch was immense. Related to this was the demand for information about the Luftwaffe’s strength as it launched its campaign to establish air superiority over Great Britain. As he does elsewhere throughout the text, Hinsley shows the fragmentary and often conflicting details that the intelligence services received, the accuracy of which was only clear with hindsight. Estimates of the first-line strength of German bomber forces, for example, proved greatly inflated, which in turn exaggerated the threat posed to Britain by the campaign. Even when accurate intelligence was available, assessing and disseminating it in time proved challenging, especially given the equally important need to maintain operational security. Nevertheless, Hinsley dismisses the claim that the latter led to any failure to provide advance warning of the infamous raid on Coventry, citing instead a combination of poor timing and the failure of the countermeasures instituted as the reasons why intelligence did not prevent the city’s devastation.
With the passing of the threat of invasion, British intelligence services now found themselves adapting to the demands of a greatly expanded war. As British forces fought U-boats in the Atlantic and Italian troops in North Africa, the range of tasks they were called upon to perform only increased. Again, the story in these chapters is one of continuing improvement, as the British grew more successful in collecting information. Analysis continued to lead decision-makers astray, though. Sometimes this was because of persistent assumptions that were difficult to give up, such as that Germany had to defeat Britain before commencing operations elsewhere. This led, among other errors, to the misinterpretation of Germany’s moves in the Balkans as a prelude to offensive operations against Britain in the Middle East rather than a securing of the southern flank in preparation for Operation Barbarossa. It was not until early June 1941 that the weight of opinion shifted towards accepting the likelihood of such an invasion, even if to the eve of the invasion itself British officials did not entirely abandon their belief that its goal was to extract concessions rather than to conquer the Soviet Union.
This persistent gap between information and the conclusions drawn from it is one of the most fascinating aspects of Hinsley’s book, and demonstrates the value of studying this aspect of the war. Yet there is a frustrating reticence to providing details that goes beyond any sort of lingering secrecy. Individuals usually go unmentioned; the now-famous Alan Turning, for example, receives just one brief mention, which is more than can be said for any of his fellow cryptanalysts. Instead, what the reader is given is a flood of abbreviations, learning that translations sent to the Admiralty “should be sent to the OIC direct from GC and CS and in undisguised form; but MI and AI received the decrypts via SIS disguised as SIS reports – initially from agent ‘Boniface’, later prefixed ‘CX’”.(p. 138) Though a helpful guide is provided at the start of the book, it can be annoying to see even familiar names like the Luftwaffe reduced in the text to “GAF,” which may have been convenient for the authors, but do nothing to improve the readability of this dense yet valuable work.
Yet in all of these volumes, something was missing. For all of their thoroughness, one aspect of the war was mostly absent from the narrative – the impact of intelligence operations on decision-making. Though there were occasional references to the information obtained, these were deliberately vague and mentioned in passing only. The reason for this was simple: in the immediate aftermath of the war, many of the means of obtaining it were still classified and thus could not be discussed officially. With the reduction in the 1960s of the closure period for official records from fifty years to thirty, however, much of the material about these activities became public in the early 1970s, making possible at last the incorporation of intelligence activities into the official account.
The task of writing intelligence activities into the history of the war was assigned to a team led by Francis Harry Hinsley, a historian familiar with wartime intelligence work from his time as a cryptanalyst at Bletchley Park. What he and his co-authors provide, however, is not an insiders’ account of code-breaking or novel-esque narratives of secret agents conducting espionage inside Nazi-occupied Europe, but an analysis of what information was collected and the role it played in shaping the decisions made by British political and military leaders. It is one that demonstrates just how wide the gap is between fiction and fact in the reputation enjoyed by British intelligence services today, and how much work they had to do make an effective contribution to Britain’s wartime efforts.
This work was necessary given the general neglect of intelligence during the interwar era. Suffering from the inevitable budgetary reductions in the aftermath of the First World War, both the military intelligence branches and the civilian-led Secret Intelligence Service (SIS) and Government Code and Cypher School (GC & CS) were parsimoniously funded until practically the eve of the war. This was exacerbated by a lack of coordination, as the various services guarded jealously their prerogatives from encroachment. This inhibited the collection and collation of information as British officials attempted to assess the capabilities of a resurgent Germany in the 1930s and their readiness for war, which contributed to many errors in judgment.
Offsetting this to some degree was the intelligence obtained or inherited from Britain’s allies, such as the Polish efforts to crack Enigma and the Czech intelligence asset Paul Thümmel, whose “A-54” designation recurs throughout the text. Yet for the first several months of the war, there was little in the way of inter-departmental coordination, as the intelligence branches struggled with adjusting to the new circumstances of the war. This contributed to the Germans’ success in obtaining surprise with their invasion of Norway, as what information was available was not pieced together in time for the Allies to prepare. While such success was not possible for German plans for Western Europe, the details of it were successfully concealed. Yet for all of their failures in the spring of 1940 and the disasters to which those failures contributed, British intelligence was adapting to the demands of war, learning not just how to acquire better intelligence, but to use it more effectively and in a timely manner.
Such adjustments could not come soon enough, as by the summer of 1940 British intelligence was facing their most urgent problem of the war. With the threat of invasion looming, the pressure to provide both details about the preparations and, most importantly, the date of its launch was immense. Related to this was the demand for information about the Luftwaffe’s strength as it launched its campaign to establish air superiority over Great Britain. As he does elsewhere throughout the text, Hinsley shows the fragmentary and often conflicting details that the intelligence services received, the accuracy of which was only clear with hindsight. Estimates of the first-line strength of German bomber forces, for example, proved greatly inflated, which in turn exaggerated the threat posed to Britain by the campaign. Even when accurate intelligence was available, assessing and disseminating it in time proved challenging, especially given the equally important need to maintain operational security. Nevertheless, Hinsley dismisses the claim that the latter led to any failure to provide advance warning of the infamous raid on Coventry, citing instead a combination of poor timing and the failure of the countermeasures instituted as the reasons why intelligence did not prevent the city’s devastation.
With the passing of the threat of invasion, British intelligence services now found themselves adapting to the demands of a greatly expanded war. As British forces fought U-boats in the Atlantic and Italian troops in North Africa, the range of tasks they were called upon to perform only increased. Again, the story in these chapters is one of continuing improvement, as the British grew more successful in collecting information. Analysis continued to lead decision-makers astray, though. Sometimes this was because of persistent assumptions that were difficult to give up, such as that Germany had to defeat Britain before commencing operations elsewhere. This led, among other errors, to the misinterpretation of Germany’s moves in the Balkans as a prelude to offensive operations against Britain in the Middle East rather than a securing of the southern flank in preparation for Operation Barbarossa. It was not until early June 1941 that the weight of opinion shifted towards accepting the likelihood of such an invasion, even if to the eve of the invasion itself British officials did not entirely abandon their belief that its goal was to extract concessions rather than to conquer the Soviet Union.
This persistent gap between information and the conclusions drawn from it is one of the most fascinating aspects of Hinsley’s book, and demonstrates the value of studying this aspect of the war. Yet there is a frustrating reticence to providing details that goes beyond any sort of lingering secrecy. Individuals usually go unmentioned; the now-famous Alan Turning, for example, receives just one brief mention, which is more than can be said for any of his fellow cryptanalysts. Instead, what the reader is given is a flood of abbreviations, learning that translations sent to the Admiralty “should be sent to the OIC direct from GC and CS and in undisguised form; but MI and AI received the decrypts via SIS disguised as SIS reports – initially from agent ‘Boniface’, later prefixed ‘CX’”.(p. 138) Though a helpful guide is provided at the start of the book, it can be annoying to see even familiar names like the Luftwaffe reduced in the text to “GAF,” which may have been convenient for the authors, but do nothing to improve the readability of this dense yet valuable work.
August 18, 2018
Perhaps not for the general public, but for my purposes, as I work on the sequel to A FLOOD OF EVIL, this is outstanding stuff. For example ...
... the (British) Air Ministry’s assumptions as to how the German Air Force would be used were so much modelled on the Air Staff’s own plans for the RAF that it not only neglected the available intelligence but also omitted to subject its acceptance of the prevailing opinion to technical study.
... the German bombers were ‘ not equipped for weight carrying ’ and were ‘ too small ’ to deliver on the United Kingdom the vast tonnages postulated. 85 From what was known of German aircraft it should have been possible to deduce that the long-range bomber force would have had to sacrifice much of its bomb load if it was to carry enough fuel for the flight from north-west Germany and back with or without over-flying the Low Countries. Again, the task of manufacturing, moving and storing the required number of bombs would have been truly vast, yet its feasibility was neither examined nor questioned.
... on 10 July. It became obvious by that day, after a month of scattered night raids, that the GAF had embarked on a programme of concentrated daylight attacks on ports, coastal convoys and aircraft factories with the object of wearing down the RAF’s fighter defences in the south-east. By mid-August it had failed in this object but could no longer defer the decision to increase the scale of its attack and seek the direct destruction of the RAF on and over its airfields. Unless this was achieved without delay, the landings in England could not take place, as planned, early in September.
A Flood of Evil
... the (British) Air Ministry’s assumptions as to how the German Air Force would be used were so much modelled on the Air Staff’s own plans for the RAF that it not only neglected the available intelligence but also omitted to subject its acceptance of the prevailing opinion to technical study.
... the German bombers were ‘ not equipped for weight carrying ’ and were ‘ too small ’ to deliver on the United Kingdom the vast tonnages postulated. 85 From what was known of German aircraft it should have been possible to deduce that the long-range bomber force would have had to sacrifice much of its bomb load if it was to carry enough fuel for the flight from north-west Germany and back with or without over-flying the Low Countries. Again, the task of manufacturing, moving and storing the required number of bombs would have been truly vast, yet its feasibility was neither examined nor questioned.
... on 10 July. It became obvious by that day, after a month of scattered night raids, that the GAF had embarked on a programme of concentrated daylight attacks on ports, coastal convoys and aircraft factories with the object of wearing down the RAF’s fighter defences in the south-east. By mid-August it had failed in this object but could no longer defer the decision to increase the scale of its attack and seek the direct destruction of the RAF on and over its airfields. Unless this was achieved without delay, the landings in England could not take place, as planned, early in September.
A Flood of Evil
July 27, 2020
Warning, this is not a weekend at the beach read. It's an intense looks at the actions of British intelligence from just before the beginning of the war to Operation Barbarossa, the German's invasion of the Soviet Union in 1941. You get the disorganization of the Brits in the beginning, the refinement of the organization, the massive contribution of the Enigma Machines, and the overall effort to find information. This is a serious book for those who are interested in the intelligence effort in World War II. One down, four more to go.
Displaying 1 - 3 of 3 reviews