From Churchill and Orwell: The Fight for Freedom, by Thomas E. Ricks (Penguin, 2017), Kindle pp. 161-162:
Churchill’s growing affection for the Americans was not entirely shared in Britain by other members of his class, either on the left or right. The pro-Soviet spy ring of Anthony Blunt, Kim Philby, Donald Maclean, and Guy Burgess was motivated in part by distaste for the United States and its culture. Philby, in his own memoir, relates that Burgess delighted in publicly taking “hefty sideswipes at the American way of life in general.”
Anti-Americanism was, if anything, even more intense on the English right. “It is always best and safest to count on nothing from the Americans but words,” Neville Chamberlain had stated in December 1937. When Lord Halifax was sent by Churchill to become the British ambassador to Washington, Lord Linlithgow, the viceroy of India, wrote him a note of sympathy about “the heavy labour of toadying to your pack of pole-squatting parvenus.”
One good definition of a snob is someone who, encountering an awkward social situation, quickly assumes the other person is at fault. Nicolson personified this. On a visit to America before the war, he found the natives well meaning but pitiful: “Most of them feel kindly but are so ignorant and stupid that they do not understand my point of view.” Nor did he trust their tendency toward openness. “There is something about the smarminess of Americans which makes me see red . . . the eternal superficiality of the American race.” These doubts persisted into the war. In November 1943, he wrote to his wife, “We are far more advanced. I despair sometimes about the Americans.”
There also was a suspicion that the Americans, for all their easy grins, did not share a major British wartime goal, the preservation of the British Empire. “The President was no friend of the British Empire,” noted Harold Macmillan, who would become prime minister in 1957. “This anti-colonialism was a strong part of Roosevelt’s make-up, but he seemed to have very crude ideas as to how independence could be gradually introduced in the great colonial empires without disorder.” One of Roosevelt’s notions that the British deemed crude was his view that Vietnam should become independent. History might be different had FDR’s advocacy of Vietnamese independence not been rebuffed by the British and French.
Condescension would lead many British officials to underestimate the growing power of the United States, and then to be shocked and angry when, in 1944, the Americans began acting as the dominant partner in the relationship.