alternatehistory.com

Per Wikipedia....

As Belgium had suffered so much damage in World War I, there was little appetite within the country to involve itself in any potential European conflict. In October 1936, King Leopold III announced that Belgium would remain neutral in the event of another war in Europe as part of what he termed an Independent Policy (Politique d'Indépendance).[7] To this end, the Belgian government tried to steer a path away from alliances: leaving the Locarno Treaty, repudiating a defence pact with France signed in 1920[8] and receiving a guarantee of neutrality from Nazi Germany in 1937.[8]


Well, we know that didn't work out well for Belgium in 1939. So, let's have a 1934 reaffirmation and strengthening of the Franco-Belgian Accord of 1920 (due to Nazi rise in 1933), with Britain joining the Accord in early 1935. The immediate effect is the lengthening of the Maginot Line right across Belgium's borders with Germany, Luxemburg and the Netherlands (on the presumption that the Dutch will fall to the Germans).

Beginning in summer 1939, the BEF deploys to Belgium, not France. By end 1939, that's 310,000 British soldiers, 500 aircraft, 25,000 vehicles, etc, etc. ready to fight alongside the Belgiums. We know that the Belgiums alone fought off the Germans for over two weeks, so with British help they should hold longer.

With such a force, would the Germans bypass Belgium? If so, they'd be leaving a massive flank open directly on the German border. Perhaps Germany attacks Belgium immediately after Poland, giving Britain less time to deploy to Belgium in strength.

What if Belgium's example leads the Netherlands to also reject neutrality and to join with the alliance with Britain, France and Belgium? Surely a united western front would rattle the German high command as they prepare to invade Poland and to bring the USSR's western border closer to Berlin?
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