If one takes this series at face value, the US was alarmed by the Labour Party victory in the first postwar election in UK and felt the need to spy on the new government. However, that wasn't an accurate depiction of the Labour Party or most European socialist parties in the 1940s, many were anti-communist and alarmed by the thuggish tactics of the Soviet Union. The Labour government of Clement Atlee backed the creation of NATO and the US in the Korean War. It's also worth remembering the US was governed by New Deal Democrats at the time, the gap between the views of the Truman Administration and Atlee government wasn't that large.
