Radio-intercepts, Reconnaissance and Raids: French operational intelligence and communications in 1940

Mentioned in memoirs by a few former military intelligence officers, operational intelligence has had little attention in academic writing on the Second World War before Ultra’s decisive contributions began in 1941-42. Especially neglected has been the fighting provoked by the German offensive in 1940 that cleaved through France, Belgium, the Netherlands and Luxembourg and drove Britain off the Continent. This article tackles this gap, analysing the military intelligence/military operations interface on the French side. It assesses the contributions and shortcomings of radio-intercept intelligence, along with intelligence-gathering by air and ground reconnaissance (demonstrating that German air superiority imposed a ‘battle blindness’ on Allied commanders wanting intelligence on approach marches and formation switches more than a dozen kilometres into the German rear). It reveals that frontline infantry raiding -- redolent of intelligence-gathering techniques familiar to veterans of 1914-18 trench warfare -- was again widely employed. This proved a highly effective recourse, particularly during the positional battles on the Somme, Aisne and Oise in June 1940, filling intelligence gaps left by more technologically sophisticated but more fragile sources. The factors that kept formations fighting so as to inflict significant delays and heavy losses on the German assaults were robust communications networks (to convey operational intelligence fast enough to permit counter-manoeuvres based on it), and the preservation of French chains of command and control. When these key nodes collapsed, preventing the hard-won operational intelligence being deployed to coordinate French military resistance, the latter declined into a series of disjointed, directionless and unavailing acts of courage that could not exploit the several instances during the campaign when the Germans, too, were afflicted by battle fatigue, re-supply bottlenecks and morale wobbles.