The situation at Dunkirk in 1940 was extremely out of bounds for the British Army. Hundreds of thousands of men struggled to escape France, as the Luftwaffe swirled overhead. The Germans had advanced with terrifying speed, covering over a hundred and twenty miles in just five days. The Germans were employing the technique of Blitzkrieg.
Blitzkrieg is a military principle consisting of a surprise attack using rapid, overwhelming force-concentration that might include armored and motorized or mechanized infantry formations, knit together with close air support, preparing itself to break through the opponent’s lines of defense, then dislocate the defenders, causing misbalance amongst adversaries army by making it tricky to respond to the continuously changing front, and defeat them in a decisive “Vernichtungsschlacht: battle of annihilation.”
The idea behind Blitzkrieg was generated in the First World War when all the sides were looking for ways to break the trench deadlock. The idea of re-establishing fast-moving warfare was of real importance to Germany, because of the Versailles Treaty, the treaty that came into force at the end of the war, limited the German army to a maximum size of a hundred thousand men, which means that they have ten divisions which is a tiny amount if compared to that of the French army of the time, which was about eighty-five divisions strong.
According to J. P. Harris, one needs two things to achieve a successful Blitzkrieg. The first is the speed of movement. The whole point of blitzkrieg was to keep moving, and not stop because if one stops, there are chances of getting entangled in a battle of attrition. The force had to keep moving, and always look for the weak point in the enemy line. Second, was the speed of communications and decision-making.
The foremost aim was to find a weak point in ranks of Allied forces and apply it to a maximum mechanized pressure, so that one could reach that, and breakthrough into the rear areas. The soldier needed to be agile to be able to act flexibly, quickly, and change the axis of the attack in the blink of an eye. Perhaps, they had been told to attack down a particular axis towards a hill or a higher terrain of some sort, and they could see that their lines were well defended.
They had the opportunity to refuse to move in a particular direction if they thought that such a move could turn out to be detrimental for them. Such decisions were impromptu moves taken by the soldiers in the German army, whereas the French command decisions would take days. And speaking of the Allies, the third and the final part is an overconfident enemy. So the Allied armies were geared up to fight the First World War all over again.
They had already won the last time around, so their mindset did not change. This also meant that there was no point in fixing anything, as nothing had been damaged, and they had already emerged victorious. Therefore, they were geared up to fight a static defensive-oriented war, and they were not investing in equipment like radio communication, which helped to enable quick snap decisions to be made near the frontline.
Their primary method of communication was through inlaid telephone lines, as it was in the First World War. All one had to do with a telephone line, was cut, and then the communication was successfully disrupted. They were paralyzed; there was just indecision everywhere throughout the command structure of the French and British armies.
If all of that is put together, it works. While the regular German infantry took on the Allies in Belgium and the Netherlands, that armored spear tip found the Allied weak point in the Ardennes and rushed through it. They encircled their enemy to cause mayhem and destruction at every turn. Once the British had evacuated at Dunkirk, Germany turned south taking in weeks, what they had never managed during the whole First World War. By mid-June, they were in Paris and by the end of the month; the French had signed their humiliating surrender in the same railway carriage as Germany in 1918.
But this also raises the question that if the blitzkrieg was such a potent method of warfare, then how did Germany lose the war? The Allies stayed firmed to defeat Blitzkrieg and continued the war. The Allies, really what they want to do is turn it from this fast-moving Blitzkrieg war into a war of attrition, a war production, literally out producing your enemy. Speed is vital in any battle and therefore, equally vital is supply. The fighting men on land and in the air needed provisions.
This is the reason why Churchill was extraordinarily keen to bring America into the war, as soon as possible, so that he could bring in the American military muscle. A multitude of heavy bombs was extremely crucial and had to be ready to be delivered just where they hurt the enemy most. So, if one is fighting a war of production, it would not matter if they lost the initial battles because as long as one survives in the end, one might out-produce the enemy, and overpower them just by sheer weight of numbers.
But blitzkrieg was not quite dead yet, it was successfully used against the Soviet Union in 1941, who failed to pay heed to any of the warnings they could have gathered from the Battle of France. But once the Second World War became that war of production, and a defensive one for the Germans, Blitzkrieg was a far less useful tactic.
Despite a late attempt at the Battle of the Bulge in 1944, Blitzkrieg could not save Germany from her ultimate defeat in1945. So those factors make Blitzkrieg a necessary strategy and proved so successful only in the early part of the war. Once the Allies had learned what they were and could counter them, the Germans had got the losing hand, as in the end, there was nothing else they could do face their inevitable defeat and, lose the war.