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Corps Topographical Sections
Much to the chagrin of the RE’s, with the exception of the Intelligence Corps Officer, the manpower for the BIS’s came from the newly forming Corps Topographical Sections. Raised as an integral part of the FSC’s they were subsequently detached to Corps Headquarters where they worked under the immediate direction of the GS Intelligence. During the Somme the need for rapid dissemination of information about the constantly changing tactical situation had led to the devolution of certain aspects of map production from Army to ad-hoc topographical sections at corps level (Chasseaud, Artillery’sAstrologers. p. 224.). Although not officially authorised until January 1917 the first Corps Topographical Sections appeared in Fourth Army in December 1916. The RE’s had their own view on the role of the BIS’s:
‘Branch Intelligence Sections had been formed about the same epoch [as Corps Topographical Sections], and for some time there was considerable overlapping of work, and doubt as to their exact relative spheres. The Branch Intelligence Section was instituted for the information of the Royal Flying Corps Pilots themselves, rather than for the reproduction and sketches for Corps and Divisional Troops. The latter duty falls to the Topo Section.’. Winterbotham, Survey on the Western Front. p. 50.
In direct contradiction to the RE’s perception the Canadian Corps viewed the utility of the BIS’s differently:
‘One of the most important functions [of the BIS] is the examination of aeroplane photographs, interpreting them with respect to topography in the enemy’s country, as well as annotating works and defences prior to their issue.’ Hahn, The Intelligence Service within the Canadian Corps 1914-1918. p. 260.
Synergy between BIS and Corps Topographical Section
In reality the functions of the BIS’s and Corps Topographical Sections complemented each other. The BIO at the BIS was the conduit through which all the Corps aerial reconnaissance and photography tasking flowed. His unique position gave him oversight of the Corps operation intelligence requirements thus enabling him to quickly prioritise intelligence gleaned from aircrew debriefs, reconnaissance reports and his section’s photographic interpretation. Time critical intelligence was disseminated immediately by telephone and when necessary followed up with annotated photographs and/or photograph derived sketches. A textual summary of activity derived from any photographic interpretation would subsequently be included in the Corps INTSUM, at the latest the day after the photograph was taken. Corps Topographical Sections, although not empowered to produce formal background maps this role remained at Army level, were responsible for the production of ‘hasty’ maps and sketches at short notice to support ongoing Corps operations. The nature of the work, which included producing trench map overlays showing the latest changes and Barrage and Counter Battery overlay maps, resulted in these sections taking a more considered view of the aerial photographs taken. The results of their photographic interpretation were incorporated on the maps and sketches they produced. In addition textual summaries of activity derived from any photographic interpretation that complemented the BIS reporting would be included in the Corps INTSUM up to two to three days after the photographs were taken. Immediate ‘first phase’ reporting was being carried out by the BIS’s, whereas considered ‘second phase’ reporting was being conducted by the Corps Topographical Sections. The birth of these two sections streamlined aerial photography’s TCPED process making it both coherent and efficient, thus enabling it to support both superior and subordinate units. The positive impact of these two sections serves to support and reinforce the view presented by Andy Simpson that:
‘From being a post box in 1914, the corps was becoming a vital clearing house for information by late 1916. Andy Simpson, Directing Operations (Brinscombe, Spellmount, 2006) p. 53.
Next: Part 16 ‘Expansion of Photographic Interpretation Expertise’