It took six more months for this to break out into a major conflict. The then Allies’ reaction to the German invasion of Finland in late 1939 was to talk at length and expel Germany from the League of Nations: not the most robust response. Some clashes broke out, especially at sea, but it was not until April/May 1940 that large-scale warfare began.
1. Germany did not invade Finland. The Soviet Union — later one of the Allies — did, on 30 November 1939. That war, the Winter War, lasted until 13 March 1940. (It was revived, as the Continuation War, just after Barbarossa in June 1941). Fighting was bitter, with the Russians alone losing more than 100,000 killed or missing in action.
2. Germany was not expelled from the League of Nations as a result of the Finnish invasion — that was, again, the USSR. Germany had withdrawn from the League of Nations some seven years before, in 1933.
3. When writing that troops were “largely inactive” for “six more months” from late 1939, one must bear in mind that it was more due to the weather than a lack of planning or desire.
Hitler initially planned for the invasion of France and the lowlands to occur in October 1939. (Note that Poland did not surrender until 10 October 1939). However, that area received unusually heavy rainfall throughout September, October and November 1939. It was clear to the German planners that any attempted attack on France, Belgium and the Netherlands would founder in mud. The invasion was therefore delayed until after winter, as conditions in winter would also favour the defenders by hindering German mobility.
However the winter of 1939/40 was the coldest for between 50 to 100 years in Europe. Harbours and rivers in the UK iced over, making shipping impossible, while snow and ice-storms made aerial manoeuvres impossible. The winter did not break until around 20 February 1940.
German and Allied forces were quite active in the intervening time, within the confines of the weather:
- in November 1939, Germany annexed the Danzig corridor and began mining the Thames estuary
- in December 1939, the Battle of the River Plate took place, ending with the scuttling of the Graf Spee
- in January 1940, the Russians lost heavily at Suomussalmi
- in February 1940, the British planned the invasion of Norway; the Russians finally penetrated the Mannerheim line; and Germany started unrestricted submarine warfare
- in March 1940, the Finns finally sued for peace against the Russians
- on 9 April 1940, the Germans invaded Norway (in a campaign that would last 2 months) and Denmark. That month, the British occupied the Faroe Islands and landed at Narvik and Trondheim, fighting until their retreat at the end of the month
The invasion of France and the low countries finally commenced on 10 May 1940, while the invasion of Norway was still underway. Note that the Norwegian campaign essentially bookended that of France, Belgium and the Netherlands — it started a month earlier, but Norway did not surrender until 10 June 1940, which was one week after the end of the British retreat from Dunkirk, and just three days before the Nazis entered Paris. The Franco-German armistice was signed on 22 June 1940.
10 May 1940 was also the day that the pro-appeasement failure Chamberlain was replaced by Winston Churchill.
4. It was not just appeasement that led to the western Allies’ inertia; Britain, France and Belgium were all ill-equipped for fighting. Although the BEF landed in France at the end of September 1939, it was under-trained, ill-equipped and simply unready to fight.
Yes, it is true that the invasion of Western Europe was delayed, but the reality of intervening events and their underlying reasons are rather different from the impression given by the article.