Operation Weserübung was the codename for the German plan to invade Norway and Denmark.
The six-month break between the land-based conflict in the Polish campaign and Hitler’s sudden invasion of Denmark and Norway is known as the Phoney War. In the west, few events took place on the land or in the air in this period. Thus, public opinion in Great Britain and France was manipulated into believing that, for them, the war was not actually an issue of life and death.
The greatest victory of the Royal Navy, during the Phoney War, was the sinking of the German pocket battleship Admiral Graf Spee. Carrying out its operations in the waters off South America, Captain Hans Langsdorff had sunk ten British ships. In the battle of River Plate, the German ship resisted against the 203.2mm cannons of the cruiser HMS Exeter. It also resisted the 152.4mm cannons of the light cruiser HMS Ajax and of the Dutch cruiser HMS Achilles. Graf Spee damaged the first two quite seriously.
Hitler ordered the OKW, the Supreme Command of the German army, to begin making preliminary plans to invade Norway after the conquest of Poland. This plan, called ‘Studie Nord’ planned for only one division of German paratroopers to participate in the conflict.
The Allied planes dropped mines into the Norwegian Channels, in deep navigable channels, sheltered between fjords and in islands along the coast, from Stavanger to the North Cape. The Allies did this in the hope of forcing German ships loaded with ore to enter the Norwegian Sea, where the Royal Navy could sink them. These actions were officially known as Operation Wilfred.
The first German ships set off for the coast of Denmark. Due to its location in the Baltic Sea, the area was important for the naval control of major ports, both Russian and German. A small and relatively flat country, it was ideal for the type of war waged by the German forces. The small Danish armed forces were unable to put up a solid resistance.
The 21st Army Corps, under the command of General Nikolaus von Falkenhorst, began operations for invading Norway. The main combat force was transported towards the Norwegian shores. At the same time, troops of German paratroopers would land in airports in Oslo and Kristiansand, and also in the perimeter of the air base in Sola. This was the first airborne attack in the history of mankind.
The Allied reaction to the German invasion was quite prompt, but haphazard and extremely disorganized. Plans were changed many times, even while underway. This produced confusion and sometimes chaos. British troops, which were embarked for the Norwegian invasion, had to be disembarked in Scotland so that the battle cruisers could be chased.
The Allies landed 200km north of Trondheim, at Namsos, and at a point 305km further south, at Åndalsnes. The Allies hoped to be able to cross the snow-filled deserts stretching between the two places and capture Trondheim from the land. The commander of the British Admiralty, Major-General Frederick Hotblack, was told about this operation at the Admiralty headquarters. He later suffered a heart attack on The Mall, on the way back to his club. His successor’s plane crashed on its way to Scotland.
Even though artillery from the Oscarsborg fortress, close to Oslo, had sunk the cruiser Blücher, one of the very few victims of coastal cannons from World War II, Norway’s capital fell.
At Narvik, the Allied force which had landed at Harsted, in the Lofoten islands, would soon number 20,000 soldiers, compared with the 4,000 Germans there. Even though relations between the Allies worked well, relations between the British army and the British navy short circuited at Narvik. This happened because, unbelievably, they were acting under contradictory orders. The Admiral of the fleet, Earl of Cork and Orrery, received the order to take Narvik with any price. At the same time, the commander of the land troops, Major-General Pierse Mackesy, was authorised to wait for the thaw before taking the city.
Operation Weserübung was a major success for Germany. Germany took Norway, and especially Denmark, by surprise. Denmark was defeated in only a few hours. After the end of the military operations in the two countries, a period of military occupation followed, which continued through the war.
Once France fell, the Germans took possession of the iron deposits in Alsace-Lorraine and the Atlantic ports. These took the place of the ports of Gällivare and Trondheim. However, approximately 201,000 square kilometers of Norwegian territory still needed garrisons for a good part of the war. These garrisons needed to shelter at least 12 German divisions, a total of 350,000 men.
The German invasion of Denmark legitimated the Allied capture of Reykjavik and the Faroe islands the following month. There, air bases were secured which were vital for the anti-submarine campaigns in the Battle of the Atlantic. After the disastrous Norwegian and Danish campaigns, Neville Chamberlain’s government was forced to resign. Thus, Winston Churchill became the new British Prime Minister.