The Divisions Légères Mécaniques (DLMs) were a product of France’s interwar effort to modernise its traditional cavalry forces in response to evolving armoured warfare concepts and lessons from the First World War. Their origins lay in the mechanisation of the French cavalry arm, blending traditional cavalry doctrine with the increasing availability of tanks and motorised vehicles.

French Mechanized Light Divisions

Five Regular Army Infantry Divisions formed the professional core of the BEF, possessing greater collective training and higher equipment levels than the Territorial formations. The divisions were deployed in France between September and December 1939. They were followed between January and April by five First Line Territorial Divisions and in April by three Second Line Territorial Divisions. All divisions were engaged by the Germans as they advanced.

Commonwealth Infantry Divisions, May 1940

The 1st Army Tank Brigade was formed on 3 September 1939 and was an integral component of the British Expeditionary Force (BEF).  The core fighting power of the brigade resided in two battalions of the Royal Tank Regiment (RTR): the 4th RTR and the 7th RTR. While an 8th Battalion RTR was associated with the brigade’s broader organizational structure, this unit did not deploy to France.

1st Army Tank Brigade participated in the counter-offensive during the Battle of Arras and provided cover for the Allied withdrawal to Dunkirk.

1st Army Tank Brigade

Following the outbreak of World War Two, the 30th Infantry Brigade was reformed in the  United Kingdom on 24 April 1940. Initially comprising two Regular Army motor infantry battalions — the 1st Battalion, Rifle Brigade, and the 2nd Battalion, King’s Royal Rifle Corps, the brigade was intended to operate as part of 1st Armoured Division.

The rapidly evolving strategic situation in France, however, prevented this. Instead, the brigade was hastily deployed to Calais, arriving on 22-23 May 1940, to defend the port against an imminent German attack. The brigade was reinforced at Calais by the 1st Battalion, Queen Victoria’s Rifles (a Territorial Army motor battalion) and elements of the 3rd Royal Tank Regiment.

30th Infantry Brigade

The 1st Armoured Division deployed to France without its assigned Royal Horse Artillery regiment, which had been allocated to the British Expeditionary Force (BEF) in October 1939. Additionally, the division’s Support Group, consisting of the 30th Infantry Brigade, was detached and sent to Calais along with one of its armoured regiments. These deployments significantly weakened the division by depriving it of vital infantry, artillery, and armoured support. As a result, the division operated at a severe disadvantage, reducing its overall combat effectiveness and limiting its ability to function as a cohesive and fully equipped armoured formation.

Commonwealth 1st Armoured Division