Why did Britain care that Germany invaded Poland in 1939?

Powerful capitalist and state interests in Britain had a rivalry with Germany for markets, power and influence. They had ganged up with the French to try and keep Germany down in the First World War, but German expansionism and rearmament threatened that post first world war settlement and conflicted with their interests. read more

Poland was a new state, established after WW1, and part of the post ww1 settlement and system that Britain established after the Great War. Germany retaking their territory and destroying the polish state would the final dismantlement of that system. read more

Both had been accomplished without igniting hostilities with the major powers, and Hitler hoped that his invasion of Poland would likewise be tolerated. To neutralize the possibility that the USSR would come to Poland’s aid, Germany signed a nonaggression pact with the Soviet Union on August 23, 1939. read more