The Polish defense plan ("Plan Zachód") called for a defense of Poland's borders in case of invasion from Germany. Much of Poland's new industry and major population centers were located in the border area (particularly in Silesia); however, the lengthy border was very difficult to defend properly. The plan was criticized by some of the Polish military and Western advisors, but supported by politicians who feared the effect of abandoning a significant part of the population to the enemy without a fight, and who were further discouraged from abandoning those territories as the Polish allies (France and the United Kingdom) did not guarantee the Borders of Poland and might well decide to allow the Germans to take the Polish Corridor they demanded in exchange for peace (pursuing a policy of appeasement).