Now all roads lead to France and heavy is the tread
Of the living; but the dead returning lightly dance.
Edward Thomas, Roads

Saturday, February 6, 2021

Sources of Frontline Intelligence: Patrol Reports & Ground Observations


By Terrence J. Finnegan

Patrols and Raids Were Used to Gather Intelligence

Spies and attachés personified traditional intelligence collection, but the rapidly evolving World War I battlefield of 1914 transcended this. Furthermore, the field commander's traditional favorite force arm for intelligence, mobile cavalry, was rendered impotent with the transition to trench warfare. With each passing autumn day in 1914, demand for relevant and timely information increased as enemy forces converged to a territorial stalemate and commenced a strategy of positional war. At the front the military culture was preoccupied with trying to make sense of what constituted success in a stationary environment. They soon learned that whatever advantage there was to be attained required timely access to accurate information. Within the first year French intelligence visionary Capitaine J. De Lennoy De Bissy portrayed information's contribution in simple terms. Data was needed "to follow the destructive work of our Artillery and to register the victorious advance of our Infantry." 

Patrol Reports

Each belligerent had their own patrol reporting procedures to collect and disseminate information within the sector they were assigned. When information was needed for refining last-minute operations, trench raids were mounted either to capture prisoners for interrogation, to gather evidence from the enemy trenches or both. The raiding party had a priority to note the trench construction, including how the revetments were configured. Any article of equipment or document was a source for intelligence analysis. Captured booty such as helmets, caps, rifles, shoulder straps and identity discs complemented the analysis. Patrols were told to look for the antennae of the enemy's radio intercept device. These usually consisted of two divergent wires coming over the enemy parapet and being earthed at two points close up to the adversary's forward trench. 

An Observer in a Canadian Trench

Ground Observation Reporting

Positional war allowed continual observation of the enemy through a network of stations strategically positioned along both sides of the front line (The French referred to this as the service des renseignements de l'observation du terrain [SROT]). Telescopes, periscopes and field glasses were the tools of the trade, and the number of observers was dependent on the terrain assigned. Panorama photographs, pasted together to form a horizon-line mosaic, provided detail for infantry analysis. The panoramic mosaics were annotated with degrees marked so a bearing to a recognized permanent point could be given for all observations. Ground observation intelligence collection was not shared by all frontline positions like sentries and machine gunners. Their role required total concentration to react effectively against observed activity. Instead, the ground observer was a highly experienced infantryman who could piece together an evolving situation and report in a timely manner back to intelligence elements or artillery units.

Model of a Camouflaged Observation Post


Both sides [meantime] conducted a war of deception, trying to defeat the enemy's perception of reality. . . Trench activity emphasized deception wherever possible, using cover of darkness or moving activities underground. What remained above ground was often a mirage created with camouflage netting in vast arrays designed by master artists. Operations in the forward areas, including construction of dummy trenches and batteries as well as feints from diversionary raids and maneuvering artillery, all contributed to this war of illusion. 

From "Military Intelligence at the Front," Over the Top, February 2009


  1. The list of prominent artists who were camofleurs in WWI includes Paul Klee and Frank Marc

  2. Paul Klee and Franz Marc if my memory serves me correctly did some beautifully rich in colour poignant striking works in the German school during the interwar period. Now in the multi million dollar price range.