Polish defence plan
What number of Polish forces participated in the Polish Corridor?
Invasion of Poland
The Polish political determination to deploy forces directly at the German-Polish border, based on the Polish-British Common Defense Pact, shaped the country's defence plan, "Plan West". Poland's most valuable natural resources, industry and population were located along the western border in Eastern Upper Silesia. Polish policy centred on their protection especially since many politicians feared that if Poland were to retreat from the regions disputed by Germany, Britain and France would sign a separate peace treaty with Germany similar to the Munich Agreement of 1938. The fact that none of Poland's allies had specifically guaranteed Polish borders or territorial integrity certainly did not help in easing Polish concerns. For these reasons, Poland disregarded French advice to deploy the bulk of their forces behind the natural barriers such as the Vistula and San rivers, even though some Polish generals supported it as a better strategy. The West Plan did permit the Polish armies to retreat inside the country, but it was supposed to be a slow retreat behind prepared positions and was intended to give the armed forces time to complete its mobilization and execute a general counteroffensive with the support of the Western Allies. The Polish General Staff had not begun elaborating the "West" defence plan until 4 March 1939. It was assumed that the Polish Army, fighting in the initial phase of the war alone, would be compelled to defend the western regions of the country. The plan of operations took into account, first of all, the numerical and material superiority of the enemy and, consequently, assumed the defensive character of Polish operations. The Polish intentions were: the defence of the western regions judged as indispensable for waging the war, the taking advantage of the propitious conditions for counterblows by reserve units, the avoidance of being smashed before the beginning of Allied operations in the West and the making of decisions depending of the existing situation. The operational plan had not been elaborated in detail and concerned only the first stage of operations. The British and French estimated that Poland should be able to defend itself for two to three months, while Poland estimated it could do so for at least six months. Poland drafted its estimates based upon the expectation that the Western Allies honor their treaty obligations and quickly start an offensive of their own. In addition, the French and British expected the war to develop into trench warfare much like World War I. The Polish government was not notified of this strategy and based all of its defence plans on promises of quick relief by their Western allies. Polish forces were stretched thinly along the Polish-German border and lacked compact defence lines and good defence positions along disadvantageous terrain. This strategy also left supply lines poorly protected. One-third of Poland's forces were massed in or near the Polish Corridor, making them vulnerable to a double envelopment from East Prussia and the west. Another third were concentrated in the north-central part of the country, between the major cities of Łódź and Warsaw. The forward positioning of Polish forces vastly increased the difficulty of carrying out strategic maneuvers, compounded by inadequate mobility, as Polish units often lacked the ability to retreat from their defensive positions as they were being overrun by more mobile German mechanized formations. As the prospect of conflict increased, the British government pressed Marshal Edward Rydz-Śmigły to evacuate the most modern elements of the Polish Navy from the Baltic Sea. In the event of war the Polish military leaders realized that the ships which remained in the Baltic were likely to be quickly sunk by the Germans. Furthermore, the Danish straits were well within operating range of the German "Kriegsmarine" and "Luftwaffe", so there was little chance of an evacuation plan succeeding if implemented after hostilities began. Four days after the signing of the Polish-British Common Defense Pact, three destroyers of the Polish Navy executed the Peking Plan and consequently evacuated to Great Britain. Although the Polish military had prepared for conflict, the civilian population remained largely unprepared. Polish pre-war propaganda emphasized that any German invasion would be easily repelled. Consequently, Polish defeats during the German invasion came as a shock to the civilian population. Lacking training for such a disaster, the civilian population panicked and retreated east, spreading chaos, lowering troop morale and making road transportation for Polish troops very difficult.