[2][3][4] The United Kingdom had been attempting to create a four-way alliance to contain Nazi Germany, with France, Poland and the Soviet Union.
Beck, however, saw an opportunity and so he proposed a secret agreement on consultation to British Foreign Secretary Lord Halifax that was received on 24 March 1939.
When questioned by Halifax, Polish Ambassador to the United Kingdom Edward Bernard Raczyński said that Beck had British aid in mind in the event of an attack on Poland, but it would not be a mutual agreement.
"[8] On 6 April, during a visit to London by the Polish foreign minister, it was agreed to formalise the assurance as an Anglo–Polish military alliance, pending negotiations.
[15] On the night of 25–26 August, a German sabotage group, unaware of the delay, made an attack on the Jablunkov Pass and Mosty railway station in Silesia.
[16] After the German occupation of Prague in March 1939 in violation of the Munich agreement, the Chamberlain government in Britain sought Soviet and French support for a Peace Front.
Although Hitler was escalating threats against it, Poland refused to allow Soviet troops to cross its border due to the risk that they would never leave.
The Soviet Union then changed its strategy and focused on expanding its sphere of influence in Central and Eastern Europe in cooperation with Nazi Germany, which ultimately led to the signing of the Molotov-Ribbentrop Pact and the joint German-Soviet invasion of Poland.
[24][25] Hitler was then demanding the cession of the Free City of Danzig, an extraterritorial highway (the Reichsautobahn Berlin-Königsberg) across the Polish Corridor and privileges for the ethnic German minority within Poland.
[26] However, there were provisions regarding "indirect threats" and attempts to undermine either party's independence by means of "economic penetration" in a clear reference to the German demands.
The Polish ambassador in London, Edward Bernard Raczyński, contacted the British Foreign Office to point out that clause 1(b) of the agreement, which concerned an "aggression by a European power" on Poland, should apply to the Soviet invasion.
Halifax responded that the obligation of British government towards Poland that arose out of the Anglo-Polish Agreement was restricted to Germany, according to the first clause of the secret protocol.
The publicist Stanisław Mackiewicz stated in the late 1940s, "To accept London's guarantees was one of the most tragic dates in the history of Poland.
Józef Beck wrote in his memoirs, "The negotiations, carried out in London by Colonel Adam Koc, immediately turned into theoretical discussion about our financial system.