In the ruins of a Belgian city. Civilians are fleeing for safety as a British soldier is crouching behind his machine-gun awaiting an enemy attack.

The offensive in the West was originally planned for 12 November 1939. It had to be carried out by 67 divisions organized in three army groups. Yet controversies in the command of the German armed forces, shortages of war materials, and severe winter caused that the date of invasion had to be postponed; and it was postponed 29 times. Eventually, when bad weather conditions put air forces' operations in question, and made it impossible to attack on 17 January 1940, the date of the offensive was postponed till the spring. Troops, designated for the invasion, were kept on alert, rotated occasionally for their rest. Constant menace from the German side forced the Allies to expect an attack at any moment, and that, as the time past, lowered psychological resistance of the Anglo-French troops.

And then happened so-called Mechelen incident - a small German transport plane crash-landed in the vicinity of the town, and two German officers, carrying with them a large part of the operations plan for the attack on the West, were captured. But king Leopold chose to ignore the matter, suspecting a provocation. But the Germans took that incident seriously, and worked out a new plan of the campaign, in the version proposed by Gen. Erich von Manstein. The plan was in effect since 24 February 1940 in the form of a directive to the land forces.

The directive foresaw offensive with 136 divisions. The main effort was on the Army Group A (Col.-Gen. Gerd von Rundstedt). It comprised the 4th, 12th and 16th Armies (45 divisions, including 7 armoured and 3 motorized). Its task was to advance in the south to the line Liege - Charleroi, along the axis Mayen - St.Quentin, in a 170km-wide sector from Roetgen to the crossing point of the borders of Germany, France and Luxembourg. It had to seize bridgeheads on the Moselle, between Dinant and Sedan, wedge in between the French 9th and 2nd Armies, envelope French fortifications of the Maginot Line, and pursue the enemy to the mouth of the River Somme. Seven armoured divisions, supported by motorized infantry, were to play the decisive role - after the passing of the mountainous massif of the Ardennes, they had to cross the Moselle and break French defences straight away.

Breaking through the Belgian fortifications was left to the Army Group B (Col.-Gen. Fedor von Bock), comprising the 18th and 6th Armies - altogether 29 divisions, including 3 armoured and 2 motorized ones. They were to operate in the whole sector north of the line Liege - Charleroi to the North Sea, and divert as much of Anglo-Franco-Belgian forces from the main axis of attack as possible. A supporting thrust was to be driven to Holland. Special tasks were given to airborne groups, which had to be dropped in many vulnerable points, seize numerous bridges and dams, penetrate so-called "Fortress Holland", and paralyze the system of the state administration and military command.

The task of the Army Group C (Col.-Gen. Wilhelm Ritter von Leeb) was to contain the enemy forces that might be transferred elsewhere. It comprised the 1st and 7th Armies - 19 divisions deployed along the Siegfried Line, in front of the Maginot Line. On 27 March to its passive task were added offensive orders: in favourable conditions it was to advance in a chosen sector between Strasbourg and the Swiss border.

In the reserves the Germans kept 42 divisions. Two air fleets, 2nd and 3rd, had to support land forces. It was a precise plan, and it had co-ordinated all the factors decisive for a "lightning war" (Blitzkrieg).

On the other hand, the French military doctrine was entirely defensive, prepared for protracted trench warfare. Intelligence information diverted the attention of the French command from the Saarland to the north. Movements of the German rapid forces (armoured and motorized troops), whose concentration was identified on the western bank of the Rhine, as well as the presence of the 6th Army's headquarters in Dusseldorf, suggested that the German thrust would be driven across Holland and Belgium. Therefore, the French had corrected their strategic plan Dyle, by including outflanking manoeuvre Scheldt (Escaut in French), later extended to include advanced manoeuvre Dyle, and extended further by adding manoeuvre Breda.

On 20 March 1940 the commander in chief of the Allied forces in north-western France, General Joseph Georges, issued secret Instruction No.9, in which he had specified the tasks of the forces of the 1st Army Group assigned to the plan Dyle. Even that plan was purely defensive. It issued from the assumption that the main German effort would be driven on the right wing, across Belgium north of the line Liege - Namur; in other words - that it would be a copy of the Schlieffen plan from the beginning of the First World War. In order to forestall the Germans, the Allied command decided to assume defences along the line Namur - Antwerp, along the River Dyle, and fight a battle in the fields of Belgium, where they expected to encounter the bulk of the German armoured and motorized troops. The manoeuvre had to be carried by the 1st Army Group (General Gaston-Henri-Gustave Billot), comprised of 1st, 2nd, 7th and 9th Armies, as well as the British Expeditionary Force (Gen. John Gort) - altogether 41 divisions.

The Belgian government gave its secret consent for deployment of the 1st Army, left wing of the 9th Army, and the British troops along the Dyle, traversing Belgium from south to north. There they had to bring the German advance to a halt. The 7th Army had to be moved (partly by sea) to the area north of Antwerp, to the Dutch territory. The 2nd Army and the right wing of the 9th Army were deployed along the Meuse, between Longwy and Givet.

The 2nd Army Group (Gen. Gaston Prételat) assumed defences along the Maginot Line from Longwy to Selestat. It comprised 3rd, 4th and 5th Armies, altogether 39 divisions. The task of the 2nd Army Group was to hold the enemy on the heavily fortified line and deny it access to the hinterland.

The 3rd Army Group (General Antoine Besson) comprised the 8th Army and the XLV Army Corps - altogether 11 divisions. It was deployed to defend so-called Belfort gap and communications with Switzerland; the Allies deemed it possible that the Germans might violate Switzerland's neutrality and attack across that country.

This short comparison illustrates that the plans of the opposing sides differed diametrically. The German plan had weighed on the fates of the 1940 campaign which were decided in two strategic battles: first - Battle of the Flanders, and second - Battle of France. Yet the Battle of the Flanders had the decisive impact on the fates of France.

The German offensive started on 10 May 1940 with massive bombings of the objects located in Holland, Belgium and France even as far as 400km behind their eastern borders. Attacked were airfields, communication nodes, commanding posts and industrial targets. Simultaneously the German air forces bombed the German city Freiburg, and accused Belgian and Dutch air forces in that to justify the aggression against those two countries. At 5:35 German land forces crossed the borders of Holland, Belgium and Luxembourg, starting the hostilities. Luxembourg surrendered practically without fights. In the rears of the Dutch and Belgian forces landed airborne troops on gliders and parachutes. They seized untouched bridges on the Albert Canal, as well as fort Eben-Emael.

Meanwhile the troops of the 1st Army Group were put on combat alarm. At 6:30 the supreme commander of of the Allied forces, French General Maurice Gustave Gamelin, informed General Georges that the Germans had violated the neutrality of Belgium, which called for help. He ordered to commence the Dyle manoeuvre, and confirmed validity of the Breda manoeuvre assigned to the 7th Army. Once set in motion, the troops marched out to meet the advancing German armies.

The Belgian army (nominal commander-in-chief - king Leopold II, Chief of General Staff - Gen. François Fidèle Oscar Michiels), organized in seven army corps and one cavalry corps, assumed defences along the line Arlon - Liege and on the fortified positions around Antwerp. There were concentrated 14 divisions. Another 3 divisions were deployed on the line of the River Meuse. A cavalry division assumed defences along the River Gette. The VI Corps, reduced to one infantry division, was shifted to a rear position defending Brussels. Three divisions were left in the reserve of the supreme commander.

On 10 and 11 May, in the sector of the advance of the Army Group A, first German troops encountered French cavalry outposts from the 9th and 2nd Armies. At night from 10 to 11 May, Belgian troops starter withdrawing to the line of the River Dyle. They were followed by the first echelon of the Army Group B.

On 12 May most of the French cavalry divisions had pulled out beyond the Meuse. During the pursuit after them, German armoured troops reached the eastern banks of the Meuse in the sector between Namur and Sedan. German motorized units at that time were way ahead of their infantry divisions, which lagged one day of march on foot behind. Yet the French forces had failed to exploit that advantage.

German advanced units undertook crossing the river without waiting for the arrival of the bulk of their forces: XV Armoured Corps (Gen. Hermann Hoth) at Dinant, XLI Armoured Corps (Gen. Georg-Hans Reinhardt) at Montherme, and the XIX Armoured Corps (Gen. Heinz Guderian) at Sedan. The river was forced at night from 13 to 14 May. It was a complete German success. From the bridgeheads on the western bank of the Meuse, German armoured divisions thrust into the French rears, wreaking havoc, commotion and panic.

Meanwhile the 12th Armoured Army advancing in Holland linked with airborne groups around Rotterdam. Dutch forces (11 divisions) pulled out to the new defence line - a series of water based defences known as the New Water Line. Yet, they were not able to hold it, and once their defence was broken, Dutch forces capitulated on 14th May. Queen Wilhelmina and the Dutch government flew to London. Although the Supreme Military Commander, Gen. Henri Gerard Winkelman, signed the act of surrender of the Dutch forces, the Germans bombed Rotterdam and destroyed the historic downtown of this old and beautiful city.

And the ability of the French command to keep the situation under control was limited, since almost all reserve divisions were already assigned to the fighting armies. After all, French generals still did not realise the gravity of the situation, even when the German armoured divisions got to the western bank of the Meuse. Gamelin still had three armoured divisions concentrated around Reims, but he regarded them for reserve units designated to reinforce infantry divisions and corps in the menaced sectors. The 1st Armoured Division, sent to plug the gap in the front west to Dinant, became immobilized due to the lack of fuel, and was wiped out by the armoured corps under the command of General Hermann Hoth. The 3rd Armoured Division exhausted its forces in the static defence in the south of Sedan. The 2nd Armoured Division was sent to reinforce the defence on the middle Oise and the Oise-Sambre Canal, but the armoured corps of Gen. Heinz Guderian caught its units unloading from the trains near St.Quentin and destroyed them piece by piece.

Thus on 10 to 15 May 1940 German forces achieved an enormous operational success: they passed the "impassable" Ardennes, crossed the Meuse, forced the Dutch to capitulate, and broke through the French defences between the 2nd and the 9th Armies. In that situation the Allied command ordered the general retreat of the entire northern wing of its forces, which became exposed to being cut off the main forces and encirclement. Between 16 and 21 May that retreat turned into a race with the German troops towards the sea. Once the Germans reached Abbeville, the northern wing of the Allied forces got trapped. On 19 May the government decided to dismiss Gamelin from command, and replace him with General Maxime Weygand, thereto the commander of the Army of the Levant; also lower levels of the chain of command saw many changes. They were coupled with the reshuffling of the French government: Marshal Philippe Pétain became deputy prime minister. Those two appointments were very unfortunate, because they reinforced the positions of the capitulationists. Paul Reynaud retained the office of the prime-minister, and took the portfolio of the minister of defence; Edouard Daladier became the foreign minister, and Georges Mandel - the minister of interior.

However, no political leapfrogging could save the situation as the German forces just began to liquidate gradually the 1st Army Group.