Swedish iron ore was an important economic and military factor in the European theatre of World War II, as Sweden was the main contributor of iron ore to Nazi Germany. The average percentages by source of Nazi Germany’s iron ore procurement through 1933–43 by source were: Sweden: 43.0%; domestic production (Germany): 28.2%; France: 12.9%. Within the German military the Navy was most dependent on Swedish steel as an absolute necessity to the German war effort, according to their grand admiral. It has also been argued that the Swedish export helped prolong the war.
Both the Allies and the Axis were keen to gain control of the mining district in northernmost Sweden, surrounding the mining towns of Gällivare and Kiruna. The importance of this issue increased after other sources of iron were cut off from Germany by the Allied naval blockade during the Battle of the Atlantic. Both the planned Anglo-French support of Finland in the Winter War and the following German occupation of Denmark and Norway during Operation Weserübung were to a large extent motivated by the wish to deny their respective enemies iron critical for wartime production of steel.
Winston Churchill, then First Lord of the Admiralty, was particularly concerned about Swedish exports of iron ore to Germany, and pushed for the British government to take military action to end the trade. From the beginning of the war Churchill tried to persuade his cabinet colleagues to send a British fleet into the Baltic Sea to stop Swedish iron reaching Germany from the two Swedish export ports, Luleå and Oxelösund. The planned incursion was termed Project Catherine and was planned by Admiral of the Fleet William Boyle. However, other events overshadowed the incursion and it was canceled. Later, when the Baltic ports froze over and the Germans began shipping the iron ore from the Norwegian port of Narvik, Churchill pushed for the Royal Navy to mine the west coast of Norway to prevent the Germans travelling inside neutral territorial waters to escape Allied Contraband Control measures.
Background
frame|Iron ore is extracted in [[Kiruna and Malmberget, and brought by rail to the harbours of Luleå and Narvik.<br>(Borders as of 1920–1940.)]]
At the outbreak of hostilities on 3 September 1939, Britain and France having vastly more powerful naval forces at their disposal swiftly enacted a repeat of the German naval blockade used to great effect throughout the previous war. Germany had limited natural resources and was reliant on large scale imports for a wide range of goods and raw materials, including iron ore, a steady supply of which was imperative in the creation of steel to sustain its war effort and general economy.
{|
|+Prewar iron ore supplies to Germany
|-
!Source
!<br>(millions)
|-
!Germany
| 10
|-
! Sweden
| 9
|-
! Other
|3
|-
!Total
|22
|-
|}
In the year before the war, Germany received 22million of iron ore from various sources. Although it was able to produce around 10million of its own iron ore each year, it was of low grade quality and needed to be mixed with high grade material from other countries such as Sweden, which annually supplied it with 9million : 7million from Kiruna and Gällivare in Lapland and 2million from the central Swedish ore fields north-west of Stockholm.
With the declaration of war and the start of the blockade, many sources of these foreign supplies were lost to Germany, and although it retained access to 3million per annum from neutral Norway and Luxembourg, the supplies from Morocco and Spain were lost to it, and so the remaining supplies from neutral Scandinavia became of crucial importance. Grand Admiral Raeder, head of the German navy, declared that it would be "utterly impossible to make war should the navy not be able to secure the supplies of iron-ore from Sweden".
Britain, who itself imported large quantities of iron ore, was fully aware of the Swedish exports to Germany and through its system of Contraband Control was routinely stopping ships of all nations to ensure they were not delivering important supplies to the Germans. To counter the allied blockade, Germany embarked upon a system of unrestricted submarine warfare whereby Allied and neutral ships could be attacked without warning. As a result, during the first nine months of the war a large number of neutral ships were sunk with considerable loss of life by the Germans.
While the Allies were keen to maintain the moral high ground and stressed at every opportunity the difference in impact between their approach compared to their enemy's, they were mindful that many neutral mariners (including those of Sweden) relied upon the trade with Nazi Germany for their livelihoods, and so during the opening stages of the war they were careful not to be too strict with non-combatant vessels for fear the blockade would alienate neutral nations into joining the war on the side of Germany.
Iron ore routes
There were two main routes by which iron ore was shipped to Germany from Sweden.
The Eastern Route
Annually from May to November, ore from the Northern region was shipped from the port of Luleå down the Gulf of Bothnia to the German north Baltic ports at Lübeck, Swinemünde, and Stettin. Outside these months, the Gulf of Bothnia froze over, severely restricting supplies, and although an alternate port was available at Oxelösund, south of Stockholm, for the transport of iron ore from the mines in Bergslagen, this facility was unable to supply the full amount required by Germany, and in any case froze over from January to March each year. Luleå remained outside the reach of Royal Navy's patrols but it was estimated that when Luleå and the Baltic ports of Oxelösund and Gävle were open it could only supply around 8million , or less than half pre-war imports.
This meant that during the early winter months of the war, due to the thick ice, Germany had no choice other than to transport the majority of its ore by rail to Narvik Station and then by ship along Norway's heavily indented Western coast to Germany, a much more circuitous route than the one available during warmer months.
The Western Route
The port of Narvik, high above the Arctic Circle was open for iron ore shipments all year round. But the stormy Atlantic coast of Norway also provided another extremely useful geological feature for Germany in its attempts to continue shipping the ore and beating the allied blockade.
Immediately offshore from Norway's western coast lies the Skjaergaard (Skjærgård), a continuous chain of some 50,000 glacially formed skerries () sea stacks and rocks running parallel to the shore. A partially hidden sea lane (which Churchill called the Norwegian Corridor) exists in the area between this rocky fringe and the coastal landmass proper. Inside this protected channel it is possible to navigate the entire length of the Norwegian coast from North Cape to Stavanger. Such coastlines, sometimes known as Leadsa rough English translation for the common Norwegian nautical term Ledene () are common around ScandinaviaSkjaergaard also exist along the Swedish and Finnish Baltic coasts and off Greenland.
The Germans made great use of the Norwegian Corridor to avoid the attention of the vigilant Royal Navy and RAF. In the winter of 1939–1940 a steady stream of their specially-constructed iron ore vessels made the long trip south from Narvik, sometimes within the three-mile curtilage of neutral Norwegian territorial waters, sometimes just outside if the way appeared hazardous or the sea particularly turbulent. At the southernmost point the iron ore captains had to make a choice:
- Follow the Skjaergaard around the coasts of Norway and Sweden, down through the Kattegat and finally into the north German and Baltic ports of Lubeck and Stettin. This route was safer because it brought them much closer to the protection of the German naval patrols and Luftwaffe air cover but involved hauling the very bulky and heavy iron ore the long way overland to the industrial centres on the overburdened German railway system.
- Leave the safety of the Skjaergaard and make a dash south across the Skagerrak (the sea channel north of the Danish Jutland peninsula), and hurry down the west coast of Denmark to Hamburg and Bremen. This was the preferred route because it allowed the ore to be taken straight along the efficient inland waterways to the industrial heartlands of the Ruhr and the Rhineland where it could be processed. It was much more hazardous, putting the ships and their cargo at the mercy of allied submarines and patrolling destroyers of the Contraband Control. A number of German ships were sunk in this area.
British attempts to disrupt trade
From the beginning of the war, Winston Churchill expended considerable energies trying to persuade his colleagues in the British government to take action to stop the iron ore traffic. On 16 December 1939 he issued a memo to the cabinet:
Although in late 1939 many of Churchill's cabinet colleagues agreed with the need to take action to disrupt the iron ore traffic, they decided against the use of mines. At the time negotiations into the British chartering of the entire Norwegian mercantile shipping fleet were at a delicate stage and the British Foreign Office made convincing arguments against infringing upon Norway's neutrality. In 1915 the British government had issued an apology to the Norwegian government for a violation of her territorial waters by British warships who seized a German steamer inside the three-mile nautical limit. Near the end of World War I the British, Americans and French had induced the Norwegians to allow the Skjaergaard to be mined in order to prevent German ships and submarines from using their territorial waters as a way around the Great North Sea Mine Barrage, a massive minefield laid from Scotland to Norway as part of the earlier Allied blockade strategy. Further, cargo ships leaving Narvik could be sunk by the Allies as Britain had declared iron ore a contraband product.
The supplies of iron ore continued to be shipped to Germany, often under Swedish naval protection through the Baltic and in some cases in Swedish transport ships. Transport of ore to Germany through the port of Luleå ended in 1944.
Sweden also sought to maintain its traditional ties with the Western democracies. The Allied blockade of Europe and the German counter blockade of the Baltic prevented all but the bare minimum of commodities such as oil reaching Sweden from the West, but despite the Allies' sympathy with Sweden's position, there was a general belief among the American and British governments that Sweden went too far in collaborating with the Nazi regime.
The Allies noted that without the Swedish iron ore, the German war effort would grind to a halt because not only was the ore being sent in large quantities but it was also of very high quality, making German steel manufacture extremely efficient. The US military was also appalled at Sweden for escorting German ships, allowing use of its own ships to transport the ore and for its failure to stop the transit of German soldiers and war materials across its territory.