This text is missing some spaces, please add them: ThustheBritishGovernmentfounditselfbetweenthreatsofSovietattack,ontheonehand,andahostility,apparentlysurprisingtoit,fromtheWhiteHouse,ontheother.
Thus the British Government found itself between threats of Soviet attack, on the one hand, and a hostility, apparently surprising to it, from the White House, on the other.