In May 1940 the German army was poised to invade the Low Countries and France. Code named Fall Gelb (case Yellow), the invasion was to result in a devastating defeat for the Allied armies.
Central to the plan were the Panzer divisions; fast mobile units that could punch a hole in the enemy defences and then drive rapidly into the rear, attacking the lines of supply and communications and rendering the Allied forces incapable of any co-ordinated action.
A Panzer IV - the largest German tank that took part in Fall Gelb. This one is a type (Ausfuhrung) D and was used to support attacks.
It had a crew of 5, a 75mm cannon and two machine guns, up to 30mm thick armour plate and could travel at 25 miles per hour.
Supported by Stuka dive bombers the panzers proved to be unstoppable.
A diversion drew the allied armies into Belgium and then the Panzer divisions attacked through the Ardennes, a heavily forested area thought to be totally unsuitable for tanks. The Panzers reached Calais on the coast in a matter of weeks, forcing the French to retreat and the British to evacuate at Dunkirk.
It was a masterpiece of operational warfare that eventually led to the surrender of the French and, although operation Dynamo managed to secure the evacuation of over 300,000 allied troops from Dunkirk, it effectively drove the British from European soil for nearly four years.