Dyle Plan in the Battle of France

The Dyle Plan or D Plan was the primary war plan of the French Army to stave off the expected German attack during Fall Gelb. It was conceived by French General Maurice Gamelin in 1940. The main objective of the plan was to stop the advancing German Army, incorrectly supposed as the strongest, in central Belgium.

During the Battle of France there were some strategic reason dictated the Allied decision to advance and fight on Belgian territory when the German attack came in the west. The British government insisted that the Flemish coast stay under Allied control so as not to threaten British naval superiority.

The French determined that the German offensive had to be contained as far east as possible, to keep the battle off French territory. Finally, the most convincing argument for advancing and fighting on Belgian territory was the Gamelin did not consider the French army capable of winning a mobile battle against the German army in the extensive operational theatre France would present. Belgium presented a far narrower from to contain German formations. The advance to the Dyle River and preparing an entrenched front there saved most of Belgium’s industrial regions from falling into German hands.

The first step took to propose the “Escaut” variant as an option for Plan d, the code for the “Dyle plan”. This would include an advance by the French into the German territory. The powerful French first and ninth Armies would hold the line in Belgium from Wavre to Givet. The French seventh Army would hold the line on the Scheldt and link up with German forces.

Gamelin made the reasonable hypothesis that the Germans would try to attempt a breakthrough by concentrating their mechanized forces. They could hardly hope to break the Maginot Line on his right flank or to overcome the Allied concentration of forces on the left side.  That only left the centre, but most of the centre was covered by the river Meuse. Tanks were limited in defeating fortified river positions. However, at Namur the river made a sharp turn to the east, creating a gap between itself and the river Dyle. Gamelin decided to concentrate half of his unbreakable reserves there; sure the main German thrust would be on the Belgium-Dutch basic.

Gamelin continued with his plans in spite of repeated criticism from his subordinates. The development of Allied strategy was exclusively in the hands of the French. The British, recognizing they were the smaller partner in the alliance, agreed to French proposals.

Made by Valeria Pretell