How the Polish Guarantee helped provoke war

The Foreign Office official William Strang said that the Polish Guarantee was THE reason Britain went to war:

 1.    It was the event which explicitly caused Britain to declare war on 3 September 1939: 'This morning the British Ambassador in Berlin handed the German Government a final note stating that unless we heard from them by 11.00 a.m.  that they were prepared at once to withdraw their troops from Poland, a state of war would exist between us.  I have to tell you that no such undertaking has been received, and that consequently this country is at war with Germany'. 

 2.    When it was made on 30 March 1939, the Guarantee was seen as a formal end of appeasement.  Appeasement was about negotiating each issue according to its merits; the Guarantee was about drawing a line.  It was a point which was NOT negotiable, and ultimately that was to cause the war. 

 3.    It stopped the British government making an alliance with Russia.  Stalin could see that Russia would end up going to war with Germany to keep Britain's guarantee to Poland. 

 4.    It stopped the British government capitulating again in August 1939.  During the Danzig crisis, on 26 August 1939, Hitler proposed a non-aggression pact which Chamberlain and the Cabinet considered.  However, the one thing the Cabinet refused to do was to allow Hitler to invade Poland, and it was on this that the proposed agreement foundered.