As Britain's ‘First Ally', Poland played a role in most aspects of allied military strategy, not least in relation to underground resistance movements. Hence, Britain's SOE was closely involved with the Polish Underground from 1940 onwards; and SOE's ‘Polish Section' was actively engaged in operations designed to strengthen the Home Army and to maintain its links with the western powers. One of the groups of SOE agents, or Cichociemni was flown into German-occupied Poland on 31 July 1944, reaching Warsaw on 1 August.
Both the British and American governments were well aware from mid-1943 onwards that Polish underground leaders were planning to launch an insurrection against the Germans as soon as the time was ripe. A memorandum to this effect reached President Roosevelt's desk, prior to the Teheran Conference, on 23 November 1943. At no point did the Anglo-Americans advise the Polish Government that a Rising might not be opportune. On the contrary, the general climate in Allied circles constantly urged the Poles to attack the Germans and thereby to assist the allied war effort.
It is also important to stress that a period of at least seven months was available to the Allied Coalition for making contingency plans. The Red Army crossed the frontier of Poland in early January 1944, heading west, but it did not reach the Vistula until the last week of July. Throughout that time, it was reasonable to expect the Coalition to consider its dispositions in three crucial respects. The first was in Intelligence, which in the absence of any British or American officers in Warsaw, was signally deficient. The second was in the field of Military Liaison, which made little progress since the British consistently ignored all requests to send a military mission to the Polish Underground (along the lines of the mission that was operating in Yugoslavia.) And the third was in diplomacy. Everyone knew that the Red Army was marching in the direction of the capital city of a country that was formally allied to Great Britain, Yet., since the ‘Big Three' kept all major strategic decisions to themselves, and since Stalin had severed relations with the Polish Government, it was self-evident that the Western leaders alone could have approached Moscow and have prepared the political ground for an eventuality that was bound to affect the Coalition as a whole. No such initiative was taken.