How WW2 Began - Invasion of Poland - Call of Duty 2

On 1st September 1939 Germany invades Poland in defense of Danzig and the right to self determination. Two days later - frustrated by French and Italian attempts to arrange a peace conference - Britain plunges Europe into another general war. Paradoxically, Britain's "alliance" with Poland and its "legal obligations" are nowhere to be seen just two weeks later upon the Soviet invasion of Poland. Nor did Britain seem to care about the Slovakian invasion and 80 years later this event is merely taught as a random unilateral German war of conquest.