Winter War | World War II

The Soviet Union (USSR) and Finland fought the Winter War, the First Soviet-Finnish War. It started with a Soviet attack of Finland on 30 November 1939, three months after World War II broke out and ended with the Moscow Peace Treaty on 13 March 1940, three and a half months later. Despite having superior military strength, particularly in tanks and planes, the Soviet Union suffered significant losses and made little progress at first. The attack was adjudicated illegal by the League of Nations, which expelled the Soviet Union from the organization.

The Soviets demanded that Finland give significant borderlands in return for land elsewhere, citing security concerns, notably the protection of Leningrad, which is 32 kilometres from Finland's border. However, the Soviet Union invaded Finland when Finland refused. Most sources believe that the Soviet Union planned to capture all of Finland, citing the installation of the dummy Finnish Communist government and the secret protocols of the Molotov–Ribbentrop Pact as evidence, but other sources argue against this. Finland fought Soviet invasions for more than two months, inflicting heavy losses on the invaders despite temperatures as low as –43 degrees Celsius. The fights were primarily fought in Taipale, Karelian Isthmus, Kollaa, Ladoga Karelia, and Kainuu's Raate Road, but there were also fights in Salla and Petsamo, Lapland. In February, the Soviet forces reorganized and changed tactics, resuming their onslaught and defeating Finnish defences.

With the validation of the Moscow Peace Treaty in March 1940, Finland relinquished 8% of its territory to the Soviet Union. The war came to an end. The Soviet Union incurred significant losses, and the country's worldwide prestige weakened as a result. However, their successes exceeded their pre-war expectations, and the USSR gained significant territory north of Lake Ladoga. Finland's sovereignty was preserved, and its international reputation was boosted. The Red Army's poor performance encouraged Adolf Hitler, the German leader, to believe that an attack on the Soviet Union would be effective and validated negative Western perceptions of the Soviet military. After 15 months of Interim Peace, Nazi Germany launched Operation Barbarossa in June 1941, kicking off the Continuation War between Finland and the Soviet Union.

Soviet–Finnish Relations and Politics

The Russian Empire launched the Finnish War against the Empire of Sweden since 21 February 1808 to 17 September 1809, ostensibly safeguarding the Russian capital of Saint Petersburg, finally capturing and annexing Finland, transforming it into an autonomous buffer state. The Grand Duchy of Finland that resulted maintained considerable autonomy within the Empire until the late nineteenth century, when Russia began attempting to integrate Finland as part of a russification campaign to reinforce the central government and unify the Empire. Only three weeks after the announcement, Soviet Russia recognized the new Finnish government. After a four-month civil war in which the conservative Whites defeated the socialist Reds with the support of the Imperial German Army, the pro-German Jägers, and some Swedish forces, and the expulsion of Bolshevik troops, Finland gained full sovereignty in May 1918.

Finland united with the League of Nations in 1920 in search of security guarantees. Still, its principal purpose remained to cooperate with the Scandinavian countries, particularly Sweden, on information exchange and defence planning rather than military exercises or stockpiling and deployment of hardware. In 1921, the Finnish government authorized volunteers to cross the border into Russia to support the East Karelian revolt. Finnish communists in the Soviet Union plotted retaliation, staging the Pork Mutiny, a cross-border raid into Finland. The USSR and Finland signed a non-aggression treaty in 1932, which was extended for another ten years in 1934. While Finland's foreign trade was increasing, the Soviet Union accounted for less than 1% of the country's total trade. The Soviet Union merged with the League of Nations in 1934.

The Soviet Union's failure to stop the Finnish revolution was viewed as a disappointment by Joseph Stalin. He believed the pro-Finland movement in Karelia represented a direct threat to Leningrad and that Finland's territory and defences could be used to invade the Soviet Union or stifle fleet manoeuvres. Soviet propaganda portrayed Finland's ruling class as a cruel and reactionary fascist gang during Stalin's reign.

Negotiations

Boris Yartsev, an NKVD spy, contacted Finnish Foreign Minister Rudolf Holsti and Prime Minister Aimo Cajander in April 1938, suggesting that the Soviet Union did not trust Germany and that war between the two countries was a possibility. The severe collectivization and purges in Stalin's Soviet Union resulted in a negative perception of Finland, reflected in the Finnish response to Soviet entreaties. During the Great Purge, the Soviet Union killed most of Finland's communist elite, significantly damaging the USSR's reputation in Finland. As a result, the Finnish envoy to Sweden, Paasikivi, was dispatched to Moscow on behalf of the Finnish government. The Soviet mission asked that the Karelian Isthmus boundary between the USSR and Finland be relocated westward to 30 kilometres east of Vyborg. As a result, Finland dismantles all defences on the Karelian Isthmus. In exchange, the Soviet Union would give up the municipalities of Repola and Porajärvi in Eastern Karelia, an area more than double the size of the region asked of Finland.

The Soviet offer alienated the Finnish administration, but it was ultimately rejected due to public and parliamentary opposition. Finland made two counteroffers: it would lose the Terijoki area to the Soviet Union, thus doubling the distance among Leningrad and the Finnish boundary, and it would also cede the islands in the Gulf of Finland, significantly less than the Soviets had wanted.

Shelling of Mainila and Soviet Intentions

According to research conducted by several Finnish and Russian historians, the gunfire was a false flag operation because no artillery units were stationed there at the time, and it was carried out by an NKVD unit on the Soviet side of the border to provide the Soviet Union with a casus belli and a pretext to withdraw from the non-aggression pact. The Soviet war exercises in March 1938 and March 1939 were based on a scenario in which border events in the village of Mainila ignited the war.

Molotov said the event resulted from a Finnish artillery strike and asked that Finland apologize and move its forces beyond a 20–25 km line from the border. Finland denied blame for the attack, refused the requests, and sought an investigation by a joint Finnish-Soviet committee. Even afterward the Soviet Union fell apart in 1991, the subject continued to split Russian historians.

At a meeting with military historians in 2013, Russian President Vladimir Putin stated that the USSR launched the Winter War to remedy faults in determining the boundary with Finland after 1917. The size of the initial Soviet invasion decision is a contentious issue. Some sources claim that the Soviet Union intended to invade Finland completely, citing the installation of the puppet Finnish Communist government and the secret protocols of the Molotov–Ribbentrop Pact as evidence. According to Hungarian historian István Ravasz, the Soviet Central Committee decided in 1939 to restore the Tsarist Empire's previous borders, which included Finland. According to American political scientist Dan Reiter, the USSR aimed to impose a regime change to win total triumph.

Soviet Military Plan

Before the war, Soviet authorities anticipated winning the war in weeks. The dual system significantly convoluted the Soviet chain of command and nullified commanding commanders' independence. Following the Soviet victory in the battles of Khalkhin Gol on the USSR's eastern frontier against Japan, the Soviet high command split into two factions. General of the Soviet Air Force, tank expert General Dmitry Pavlov, and Stalin's favourite general, Marshal Grigory Kulik, chief of artillery, were all there on one side.

Overall Grigory Kravchenko of the Soviet Air Force and General Georgy Zhukov of the Red Army headed the other group of Khalkhin Gol veterans. Unfortunately, the lessons of the Soviet Union's first actual battle on a large scale with tanks, artillery, and aeroplanes at Khalkin Gol went unheeded under this fragmented command system. As a result, Russian BT tanks struggled throughout the Winter War, and it took the Soviet Union three months and nearly a million men to do what Zhukov accomplished in ten days at Khalkhin Gol.

Soviet Order of Battle

The success of German Blitzkrieg tactics impressed Soviet generals. With a complex, well-mapped network of paved roads, Blitzkrieg was designed to Central European conditions. Armies fighting in Central Europe had identified supply and communications hubs that armoured vehicle regiments could quickly strike. Finnish Army bases, on the other hand, were located deep within the nation. There were no flagged roads, and even gravel or dirt roads were sparse; the environment was primarily wetlands and woodlands with no tracks. "Every acre of its surface was meant to be the despair of an approaching military force," wrote war correspondent John Langdon-Davies of the landscape. Waging Blitzkrieg in Finland was a challenging task. According to Trotter, the Red Army lacked the tactical cohesion and local initiative necessary to carry out Blitzkrieg tactics in the Finnish theatre. The Soviet forces were divided into the following groups:

• The Karelian Isthmus was home to the 7th Army, including nine divisions, a tank corps, and three tank brigades. The city of Vyborg was its goal. Later, the 7th and 13th Armies were formed from the force.
• The 8th Army was stationed north of Lake Ladoga, with six divisions and a tank brigade. It aimed to perform a flanking manoeuvre around Lake Ladoga's northern side to attack the Mannerheim Line from behind.
• The 9th Army was poised to launch an attack on Central Finland via the Kainuu region. It was made up of three divisions, with a fourth on the way. Its objective was to cut Finland in two by pushing westward.
• Murmansk was home to the 14th Army, which consisted of three divisions. Its mission was to conquer the Arctic port of Petsamo before moving on to Rovaniemi.

Finnish Order of Battle

Geographical factors influenced Finland's policy. The Finnish Defence Command, which had set up its wartime headquarters in Mikkeli, predicted seven Soviet partitions on the Karelian Isthmus and no more than five throughout the entire border north of Lake Ladoga in pre-war assessments. While the Finnish Army was unable to provide suitable uniforms to all of its soldiers at the outset of the war, reservists were supplied with warm civilian attire. Finnish tank forces were non-existent in terms of operational capability. Because Finns mainly were armed with Mosin–Nagant rifles from the Finnish Civil War, which utilized the same 7.6254mmR cartridge as Soviet forces, the ammunition problem was partially improved. Nevertheless, the situation was so bad that the Finnish troops were forced to plunder the bodies of dead Soviet soldiers to keep their ammo supply going. The Finnish forces were stationed in the following positions:

• Hugo Österman commanded the Army of the Isthmus, which consisted of six divisions. The II Army Corps was on the right flank, while the III Army Corps was left.
• North of Lake Ladoga, the IV Army Corps was stationed. Juho Heiskanen, who was soon superseded by Woldemar Hägglund, commanded two divisions.
• Wiljo Tuompo led the North Finland Group, which consisted of White Guards, border guards, and drafted reservist forces.

Start of the Invasion and Political Operations

In response to the global condemnation, Soviet Foreign Minister Vyacheslav Molotov declared that the Soviet Air Force was dropping humanitarian aid to the starving Finnish population, jokingly called Molotov bread baskets by Finns. The Soviet attack without a announcement of war, according to Finnish statesman J. Paasikivi, breached three distinct non-aggression promises. The Treaty of Tartu, contracted in 1920, the non-aggression accord between Finland and the Soviet Union, signed in 1932 and 1934, and the League of Nations Covenant, signed in 1934 by the Soviet Union. C.G.E., Field Marshal On 14 December 1939, the League excluded the Soviet Union and urged its members to aid Finland. The Soviet Union formed a marionette government in sections of Finnish Karelia captured by the Soviets on 1 December 1939, dubbed the Finnish Democratic Republic and governed by Otto Wille Kuusinen.

First Fights and Soviet Advance to the Mannerheim Line

The Mannerheim Line, a collection of Finnish defence facilities that began to be known during the conflict, was positioned on the Karelian Isthmus, around 30 to 75 kilometres from the Soviet border. On the Isthmus, the Red Army had 250,000 soldiers facing 130,000 Finns. To interruption and damage the Red Army before it reached the Mannerheim Line, the Finnish command deployed a defence in depth of around 21,000 men in the area in front of the line. The most severe source of uncertainty among Finnish soldiers in combat was Soviet tanks. A typical Soviet onslaught lasted only an hour during the war but resulted in 1,000 deaths and 27 tanks strewn across the ice. The defending Finnish units on the Ladoga Karelia front relied on the terrain north of Lake Ladoga. The new Red Army did not have road networks in Ladoga Karelia, a substantial woodland area. In addition, the Soviet 8th Army had completed a new train line to the border, potentially doubling the front's supply capacity. The invading Soviet 139th Rifle Division, supported by the 56th Rifle Division, was defeated in Tolvajärvi on 12 December, the first Finnish win of the war, by a much smaller Finnish force led by Paavo Talvela.

Roads were scarce in Central and Northern Finland, and the landscape was harsh. The Finns did not expect large-scale Soviet strikes, but the Soviets dispatched eight divisions with heavy armour and artillery support. The Soviet 88th and 122nd Rifle Divisions attacked at Salla in Finnish Lapland. 

Weather Conditions

The wintertime of 1939–40 was bitterly cold, with a record low temperature of 43 °C on the Karelian Isthmus on 16 January 1940. Only those Finnish soldiers in active action had uniforms and weapons at the start of the conflict. The Soviets did not paint their equipment white or supply snowsuits to their Army until late January 1940.

The majority of Soviet soldiers wore suitable winter clothing, but not every regiment did. Because the Red Army lacked adequate winter tents, troops were forced to sleep in makeshift shelters. As a result, several Soviet battalions suffered frostbite fatalities of up to 10 percent even before crossing the Finnish border. On the other hand, cold weather aided Soviet tanks by allowing them to traverse through frozen terrain and bodies of water rather than getting stuck in marshes and muck. During the fight, at least 61,506 Soviet troops were sick or frostbitten, according to Krivosheev.

Finnish Guerrilla Tactics

The Finns isolated smaller areas of numerically more significant Soviet forces, particularly on the Ladoga Karelia front and at the Battle of Raate Road. The Finns dealt with the Soviet troops individually and assaulted them because the Soviet forces were dispersed into smaller units. Staying alive was a struggle comparable to fighting for many of the besieged Soviet troops in a pocket. He had been persuaded by Soviet propaganda that the Finns tortured detainees to death. The difficulty was that the Finns were essentially too weak to capitalize on their excellent fortune effectively.

Battles of the Mannerheim Line

Because the topography of the Karelian Isthmus prevented guerilla tactics, the Finns were compelled to use the more traditional Mannerheim Line, which was flanked by enormous bodies of water. The line was generally weaker than comparable lines in mainland Europe. The actual strength of the line, according to the Finns, was the tenacious defenders with a lot of sisu, a Finnish word approximately translated as guts or fighting spirit.

At the fight of Taipale on the eastern side of the Isthmus, the Red Army attempted to break through the Mannerheim Line. However, due to a planning error, the nearby Munasuo marsh has a 1-kilometer wide gap in the line. On 19 December, during the First Battle of Summa, several Soviet tanks burst through the thin line. Still, the Soviets could not take advantage of the situation due to a lack of cooperation amongst branches of service. Moreover, because the Finns lacked anti-tank weapons, they remained in their trenches, allowing Soviet tanks to pass freely behind their line.

Battles in Ladoga Karelia

The Red Army's strength north of Lake Ladoga in Ladoga Karelia astounded the Finnish command. On 4 December, Juho Heiskanen, the Finnish IV Army Corps commander, was replaced by Woldemar Hägglund. Finnish units retreated around the little stream of Kollaa on 7 December, in the centre of the Ladoga Karelian front. "Kollaa holds," a memorable quote, has become a legendary mantra among Finns. The sniper Simo Häyhä, called "the White Death" by the Soviets and credited with over 500 kills, added to the mythology of Kollaa. In the Battle of Kollaa, Captain Aarne Juutilainen, dubbed "the Terror of Morocco," also became a living legend. On 5 December, the Finns retreated from Ägläjärvi to Tolvajärvi, and on 11 December, they repelled a Soviet offensive in the fight of Tolvajärvi.

On the northern part of the Lake Ladoga coastal route, two Soviet divisions were connected in the south. Due to weariness, the Finns temporarily halted their assaults on 19 December. The Finns did not start their onslaught until January 6–16, 1940, dividing Soviet divisions into smaller mottis. According to Finnish expectations, the besieged Soviet forces did not try to break through to the east but instead entrenched. The motti method was frequently used as a Finnish response to the behaviour of Soviet troops under fire rather than as a plan. Despite the cold and starvation, the Soviet forces did not easily surrender and fought bravely, often encamping their tanks as pillboxes and constructing timber dugouts.

Battles in Kainuu

The northern Juntusranta road and the southern Raate road were the two roads that led from the border to Suomussalmi. During the month-long struggle of Suomussalmi, the Battle of Raate Road resulted in one of the most significant Soviet losses of the Winter War. Though Finnish Colonel Hjalmar Siilasvuo and his 9th Division cut off the withdrawal course, split the enemy force into smaller mottis, and then continued to slaughter the survivors in detail as they retreated, a small unit blocked the Soviet advance. As a result, the Soviets lost 7,000–9,000 men, while the Finnish troops lost 400. In addition, several tanks, artillery pieces, anti-tank guns, hundreds of trucks, about 2,000 horses, thousands of firearms, and much-needed ammunition and medical supplies were captured by Finnish troops.

Battles in Finnish Lapland

Rather, the Soviets dispatched entire divisions. The Finns restructured the defence of Lapland on 11 December, separating the Lapland Group from the North Finland Group. Kurt Wallenius was assigned to head the group.

The Soviet 88th and 122nd Divisions, a total 35,000 soldiers, advanced in southern Lapland towards the settlement of Salla. A Finnish battalion outflanked the Soviet northern group, which included an infantry regiment, a division, and a tank company, on 17 December. The Finns counterattacked, making the Soviets to withdrawal to a new defensive line, where they remained for the remainder of the conflict.

Petsamo, Finland's sole ice-free Arctic port, was to the north. The Lapland winter's near-constant darkness and harsh temperatures aided the Finns, who launched guerrilla strikes against Soviet supply lines and patrols.

Soviet Air Force

Thousands of rail tracks were cut, but the Finns quickly mended them, and service was restored within hours. The Soviet Air Force had learnt from its early blunders and implemented more efficient tactics by late February. On the opening day of the war, the heaviest bombing raid against Finland's capital, Helsinki. Despite this, Soviet air assaults killed 957 civilians, affecting thousands of people. The Soviets carried out 2,075 bombing assaults at 516 different locations.

A significant Soviet target on the Karelian Isthmus front, Vyborg, was almost destroyed by approximately 12,000 bombs. In Soviet radio and media coverage, no attacks on civilian targets were mentioned. The Soviet Pravda newspaper continued to emphasize in January 1940 that no civilian targets had been hit in Finland, even if mistakenly. The Soviet air force is thought to have lost over 400 planes due to bad weather, a lack of fuel and tools, and transit to the front.

Finnish Air Force

Finland had a weak air force at the start of the war, with only 114 combat planes fit for deployment. Fighter aircraft were primarily utilized to counter Soviet bombers, and missions were limited. Strategic bombs are also used as a means of gathering military intelligence. Aircraft provided little support for Finnish ground troops since they were old and few. Despite losses, the number of planes in the Finnish Air Force increased by more than 50% at the war's end. The Finns got aircraft from the United Kingdom, France, Italy, Sweden, and the United States.

Finnish fighter pilots often flew their disparate collection of planes into Soviet formations that outnumbered them by a issue of ten or even twenty. Finland's fighters downed 200 Soviet aircraft while losing 62 of their own to various causes. Over 300 enemy planes were shot down by Finnish anti-aircraft artillery. A frozen lake, a windsock, telephone equipment, and several tents were frequently used as a Finnish forward airbase. The Lotta Svärd, a group of Finnish women, issued air-raid alerts. Jorma Sarvanto was the top-scoring fighter ace, with 12.83 victories. In the Continuation War, he would add to his record.

Naval Activity

The Soviets employed naval stations in Paldiski, Tallinn, and Liepja. Two coastal defence vessels, five submarines, four gunboats, seven motor torpedo boats, one minelayer, six minesweepers, and at least five icebreakers made up the Finnish Navy. One or two planes were shot down over the city by their anti-aircraft guns, and the vessels endured there for the rest of the war. On 18 January, the Finnish armed icebreaker Tarmo was severely damaged in Kotka after receiving two bombs from a Soviet bomber, killing 39 Finnish service members. The Finnish Navy also safeguarded land islands and Finnish commerce boats in the Baltic Sea and coastal defence. Finnish ships and harbours were bombarded, and mines were dropped into Finnish seaways.

Coastal Artillery

Important harbours and naval sites were protected by Finnish coastal artillery batteries. Finland attempted to modernize its old guns by installing some new batteries, the largest of which was a 305 mm gun battery on the island of Kuivasaari in front of Helsinki, which was initially designed to block Soviet ships from entering the Gulf of Finland with the help of batteries on the Estonian side. On 1 December, at the island of Russarö, 5 kilometres south of Hanko, the first naval assignation took place in the Gulf of Finland. The Soviets knew where the Finnish coastal batteries were but were taken aback by their range. In conjunction with army artillery, coastal artillery had an enormous effect on land by bolstering defence.

Red Army Reforms and Offensive Preparations

By the third week of the battle, Soviet propaganda had already begun to explain the Soviet military's failings to the general public. The Americans incorrectly claimed that the Mannerheim Line was more potent than the Maginot Line. They had dispatched 1,000 of their best pilots to Finland, blaming rugged terrain and severe climate. On the Karelian Isthmus, all Soviet forces were divided into two armies. The Army of the Seventh and the Army of the Thirteenth. The 7th Army, now led by Kirill Meretskov, would focus 75 percent of its forces on the Mannerheim Line's 16-kilometre section between Taipale and the Munasuo marsh. The number of divisions was increased from ten to twenty-five, with six or seven tank brigades and several independent tank platoons providing backup for 600,000 personnel. The Red Army launched a massive onslaught on 1 February, bombarding the Finnish line with 300,000 rounds in the first 24 hours.

Soviet Offensive on the Karelian Isthmus

Even though the Karelian Isthmus front was less active in January than in December, the Soviets increased their bombardments, wearing down the defenders weakening their defences. The Soviets increased their artillery and air bombardments on 1 February.

Even though the Soviets improved their tactics and morale, the generals were still willing to take tremendous losses to achieve their goals. If infantry forces defended the tanks, the Finns would have a hard time destroying them. In the Second Battle of Summa, the Soviets broke through on the Western Karelian Isthmus after a 10-day artillery assault.

On the Karelian Isthmus, the Soviets had 460,000 soldiers, 3,350 artillery pieces, 3,000 tanks, and 1,300 aircraft deployed by 11 February. Mannerheim sanctioned a general withdrawal of the II Corps to a fallback line of defence on 15 February. The Finns resisted Soviet assaults on the eastern side of the Isthmus, securing a stalemate in the fight of Taipale.

Peace Negotiations

Despite the Finns' best efforts during the war to reopen dialogue with Moscow, the Soviets did not respond. On 12 February, Finnish Foreign Minister Väinö Tanner came to Stockholm to negotiate peace arrangements with the Soviets through the Swedes. On 17 February, German diplomats, unaware of the conversations, urged that Finland negotiate with the Soviet Union.

The conclusion of the Winter War was a priority for both Germany and Sweden. The Germans even devised a plan dubbed Studie Nord to invade Scandinavian countries, which subsequently became Operation Weserübung. However, as the Finnish Cabinet hesitated in the face of difficult Soviet conditions, Sweden's King Gustav V issued a public declaration on 19 February confirming that Swedish troops had denied Finnish requests for assistance.

End of War in March

On 5 March, the Red Army moved 10 to 15 kilometres across the Mannerheim Line and into Vyborg's suburbs. The Finnish government had no choice but to accept the Soviet proposals. However, it realized that the hoped-for Franco-British military expedition would not arrive in time since Norway and Sweden had refused to grant the Allies the right of passage. President of Finland at the time, Kyösti Kallio, rejected the concept of ceding any terrain to the Soviet Union but was required to sign the Moscow Peace Treaty.

Moscow Peace Treaty

In comparison to March 1938, Finland too lost 30% of its economic assets. A total of 12% of Finland's population, 422,000 to 450,000 Karelians, were forced to flee their homes. Finland gave up a portion of the Salla region, the Barents Sea's Rybachy Peninsula, and four islands in the Gulf of Finland. The Soviet Union demanded that the border among the USSR and Finland on the Karelian Isthmus be moved westbound to a point 30 kilometres east of Vyborg, along the line among Koivisto and Lipola, that present fortifications on the Karelian Isthmus be demolished, and that the islands of Tytärsaari, Suursaari, and Koivisto in the Gulf of Finland and the Rybachy Peninsula be ceded before the war. 

Foreign Volunteers

Following the signing of the Molotov–Ribbentrop Pact, Nazi Germany permitted weaponry to move through its borders to Finland, but after a Swedish newspaper made this public, Adolf Hitler instituted a policy of silence to Finland as part of enhanced German-Soviet relations.

Sweden, which offered roughly 8,760 volunteers during the conflict, had the most fabulous foreign contingent. Before the war ended, 350 Americans with Finnish ancestors volunteered, while 210 volunteers from other countries arrived in Finland. Max Manus, a Norwegian, served in the Winter War and later rose to prominence as a confrontation fighter during the German occupation of Norway. Finland received a total of 12,000 volunteers, 50 of whom perished during the conflict. Christopher Lee, a British actor, volunteered for the war and served for two weeks but did not see the battle.

Franco-British Intervention Plans

Another idea was to launch a colossal airstrike against the Caucasus oil fields with Turkish help. The British, for their part, aimed to stop iron ore from Swedish mines from reaching Germany, as the Swedes supplied up to 40% of Germany's iron demand. On 18 September 1939, British Admiral Reginald Plunkett raised the issue, and Winston Churchill brought it up in the Chamberlain War Cabinet the next day. On 11 December, Churchill suggested that the British create a foothold in Scandinavia to assist the Finns without fighting the Soviet Union. Because Germany relied heavily on Northern Sweden's iron ore, Hitler had warned the Swedish government in December that any Allied soldiers on Swedish soil would prompt a German invasion.

The French Prime Minister Édouard Daladier presented his strategy to the General Staff and the War Cabinet on 19 December. The French and British were primarily motivated by a desire to weaken Germany's ability to wage war. The Military Coordination Committee met in London on 20 December, and the French plan was presented two days later. On 27 December, the Anglo-French Supreme War Council decided to send communications to Norway and Sweden, encouraging the Norwegians and Swedes to assist Finland and support the Allies.