The Operational Connectivity between Bletchley Park, The 'Y' Service, Bomber Command & No. 100 (Bomber Support) Group 1943-45
Purpose
Work is in progress to assemble documentary evidence from World War 2 that would demonstrate the end-to-end connectivity between the initial signals intercept activity by the Y-Service; the decryption, analysis and reporting activities undertaken within Bletchley Park and other associated stations; and the operational missions of Bomber Command, including the Radio Countermeasures (RCM) role and tasks of 100 (Bomber Support) Group, within the Bombing Offensive conducted initially by the Royal Air Force and, progressively, jointly with the US Strategic Air Force Europe during the period 1943-45 in World War 2.
Specific activities by individual elements within the entire intercept, analysis, reporting and operational command and control chains have previously been documented in various ways. The current work will trace, assemble and collate material into a form that would demonstrate the overall operational use of Bletchley Park material. This material could then be available to act as a basis for display and exhibition material by the Bletchley Park Trust; the City of Norwich Aviation Museum, that supports the 100 Group Museum; and any other interested groups.
The principal parties associated with the investigation to date are the Bletchley Park Trust and The National Archives (TNA), Kew, the latter as the custodian of much original data. The other directly interested parties are the City of Norwich Aviation Museum and the UK Chapter of the Association of Old Crows.
Definitions and Boundaries
The Bletchley Park (Station X) and Bomber Command activities are assumed to be familiar to Newsletter readers, but it may be helpful to describe the:
• The Y-Service
• Function of No 100 Group within Bomber Command,
• Objectives of the Strategic Bombing Offensive, as conducted from UK airfields.
The Y-Service
Well before the outbreak of hostilities in 1939, radio signals from potential enemy countries were being monitored by UK agencies. This work expanded rapidly as the war began and there could very soon have been few enemy signals within radio range that were not liable to interception, recording and analysis. Within the UK Armed Forces, at home and overseas, the actual monitoring of radio signals, whether in low-grade or high-grade cipher, radio telephony or nonMorse transmissions, was the responsibility of the Y-Service. This Service had distinct units within the Navy, Army and Air Force. Their collective responsibility included the distribution of derived intelligence from lower grade signals to the Operational Commands. But perhaps the most vital aspect of their work, 24 hours a day and 365 days a year, was the interception of the German Enigma radio signals and the supply of that material as quickly as possible to Bletchley Park for decryption and analysis. Without those original radio signal intercepts, there would have been no Ultra material; and no Golden Eggs for the Prime Minister. But within the context of the work currently in hand, the Y-Service progressively made substantial daily contributions to the planning and conduct of the Bomber Offensive and 100 Group operations.
No 100 Group
By mid-1943 it was becoming clear that the expanding role of
RCM within Bomber Command would require the use of specialist aircraft, to carry effective radar and communications jamming deep into enemy territory in order to best engage the enemy night fighter system. Concurrently, the installation problems and operating tasks of the evolving RCM equipments were presenting increasing difficulties on the Main Force bomber aircraft. The RCM equipments consumed payload, prime power and crew effort that compromised the available bomb load and aircraft operating range. The idea was that there should be an RCM Escort Force for the bombing offensive. The decision was therefore made, at an Air Ministry meeting on 29 September 1943, to form an RCM Group that would be responsible for the operational application and co-ordination of all RCM effort, both ground-based and airborne. This was initially designated as 100 (Special Duties) Group but was later renamed as 100 (Bomber Support) Group, under the command of Air Vice Marshal Addison. The Group progressively had up to 13 separate Squadrons and several specialist Flights, using a variety of aircraft including Halifax, Mosquito, Stirling, Wellington, Fortress and Liberator types; the overall number of aircraft varied from time to time but was generally about 200.
The Strategic Bombing Offensive
Conceived at the Casablanca Conference in January 1943 by the Combined Chiefs of Staff, with the broad directive to:
“Progressively destroy and dislocate the German military, industrial and economic systems and their direct support of land and naval forces; and to undermine the morale of the German people to the point where their capacity for armed resistance was fatally weakened.”
Based on this directive, the Combined Chiefs drew up detailed plans for the Offensive. These plans were approved at the Trident Conference in May 1943 at Washington DC; this became known as the Pointblank Directive. There were subsequent revisions both to the detailed policy and to specific target priorities as the war progressed, but the fundamental objectives were unchanged.
Within the Strategic Bombing Offensive, as mounted from UK airfields, the bombing operations were undertaken at night-time by RAF Bomber Command and in daylight by the VIIIth US Army Air Force (US AAF). In general terms both night and day operations progressively benefited from a similar level of support by Bletchley Park and the Y-Service. Other Pointblank bombing operations were undertaken from the Mediterranean area, generally by the XVth US Army Air Force, but these will not be addressed within this investigation. In January 1944, the VIIIth and XVth Air Forces were merged to form the US Strategic Air Force Europe (US StAFE), under the command of General Spaatz and based at Bushey Hall, Middlesex. Soon after, in February 1944, General Doolittle took over command of the VIIIth Air Force from General Eaker, with the HQ collocated at RAF High Wycombe with Bomber Command and Air Marshal Harris. The high level Command Structure is shown below:
The work in hand will principally be concerned with the relationship between Bletchley Park and RAF Bomber Command operations, including RAF 100 Group.
Situation Report
The German Air Section at Bletchley certainly did have direct daily contact with Bomber Command HQ and subsequently with 100 Group. Quite apart from increasingly close and mutually beneficial liaison visits and frequent telephone contacts, the regular reports included the BMP series, some at PEARL/ZIP/TAC level; these eventually were prepared daily to separately support Day offensives and Night offensives. Specific BMP reports contained high-grade material and consequently had a more restricted distribution list. The BMP series was so-named after the original three compilers - Bonsall, Moynes and Prior, without whose efforts and persistence, sometimes against rather obstinate bureaucracy, these most valuable reports may have never appeared.
In many cases, the majority of the operational detail in these reports came from the Y-Service, particularly Kingsdown, Cheadle and later from Canterbury and continental sites. Enigma-derived material at Bletchley Park was progressively fused with this intercepted R/T and W/T traffic, with both sources benefiting substantially. The profound benefit of fusing together high-grade and low-grade traffic was substantially demonstrated by staff within the German Air Section at Bletchley, often against further bureaucracy and prevarication from Air Intelligence. With hindsight, it may be argued that the evolving analytical fusion process was breaking completely new ground for the intelligence community; in much the same way as was the fundamental process of Enigma decryption. These major activities were both at the leading edge of intelligence analyses and reporting techniques.
The telephone ‘hook-up’ service which connected Bletchley, Kingsdown, Cheadle and the Operations staff at Bomber Command and 100 Group provided continuous voice connection between the sites prior to and during the conduct of bombing operations, but more of this in later reporting.
What has clearly been indicated is that within the end-to-end connectivity, there are many ‘hooks’ that would permit secondary examination by way of adding depth to the overall investigation. Examples of these ‘hooks’ would include:
• Low-grade Y-Service intercepts of German Air Force air defence R/T and W/T traffic in near real time which disclosed German night fighter intentions, with the immediate use of this material by operational bombing missions in progress over Germany; for example, to provide radio frequency and radar targets for jamming support against the German air defence system, by both ground based jammers within UK and airborne jammers within the bomber forces, including of course the aircraft from 100 Group.
• The fusion of high and low grade traffic, within the internal analysis process at Bletchley Park, prior to the production of outgoing Reports that had Added Value and Timeliness for operational staffs; for example, the delivery to Bomber Command HQ of the Preliminary Versions of the analysis of that night’s raids and the German nightfighter system reactions, in order to meet the morning briefing for the Commander-in-Chief Sir Arthur Harris and his US counterpart, the Commander of the VIIIth US AAF, and the planning for the coming nights raids.
• High-grade traffic used to assist the work of the Combined Strategic Targets Committee in generating and updating the regular Bombing Target Directives. This high-grade traffic provided a source of German comment and reporting on the effects of the bombing offensive. But it will be seen that there was contention at the high command level about some of the recommendations.
Associated Factors
Other factors that may have had impact at the time were the various security partitions that were in place to protect the Enigma source; for example, for the first half of the war Bomber Command was not entitled to have access to that source. But Fighter and Coastal Commands did have access; the latter because of the operational association with the Royal Navy and the conduct of maritime warfare against surface ships and submarines.
The Air Ministry can now be seen to have had procedural flaws concerning the distribution and management of some intelligence material. With hindsight and some experience of working within the Intelligence organisation, it may well have been that some of the staffs were not aware of the needs of all the interested parties regarding the dissemination and timeliness of certain intelligence product. That would hardly be surprising in light of the rapid expansion of the services as the war progressed, but it did contribute to significant shortfalls in the timeliness of dissemination of some of the Y-Service and Bletchley-derived material.
Yet another issue is the reliability of some Enigma material. This was very clear on some occasions, especially when that material was a ‘sole source’ and the assumption was made that it must always be correct. The problem here is the perennial question about reliance on a sole source. Perhaps because of German personalities and their hierarchy, there may have been instances where there was some economy with the truth within the preparation of the original encrypted traffic. There were certainly reports at the time from Allied commanders that the source was sometimes misleading and unreliable. There is also the possibility that some people involved with the analysis and control of the material may have been seduced by the power that its possession conveyed.
A very important factor will always remain central to any intelligence analysis process: Intelligence is the servant of Policy, not the Master. National Leaders and Operational Commanders in the field must always have the option to assess but not necessarily accept the intelligence that is available; Intelligence is but one part of the jigsaw; it is the national leaders and the military commanders responsibility to assess the whole situation and make decisions accordingly.
The Way Forward
Material examined so far has shown that the purpose of the work is achievable and that it may illuminate some otherwise obscure elements of the overall conduct of Air Intelligence acquisition and operational use during World War 2 during the Strategic Bombing Offensive.
The work is expected to show how part of the massive product from Bletchley and the Y-Service had rapid, direct and indirect benefits to the operational planning and the conduct of the Strategic Bombing Offensive. The extent to which this could be presented to visitors and integrated into an overall display strategy has yet to be determined.
Subsequent reports of the evolving work will be presented in forthcoming issues of the Newsletter.
Associated Documentation
The scope and format of this documentation have yet to be determined, but provisionally the expectation is that an overview document would be produced that addresses the major ingredients of the project; together with a set of supporting documents that each address specific aspects in more detail. Each document could be in the form of a soft-bound A4 Report having 25-50 printed sheets, mostly in black text with supporting colour graphics. The first document is expected to become available by mid-2007, in phase with the possible initial display material
by John Stubbington
This article is from the Spring 2007 issue of Confound and Destroy
