Goofs

When Philby and Samantha are reading the Russian edition of the book, Samantha tells Philby that the author wrote the inscription in Russian, but when Philby turns to the front of the book to see and read it, it is written in English.

In chess, there is no such thing as "Queen's Pawn 4." It is just "Queen 4," and the square they move the bishop to would be Queen 5.

In one scene, Samantha is being pushed by a nurse in a wheelchair and there is no cast on her left arm. In the next scene she is back in bed and the cast can be seen.

When Philby entered Alexsandr's room to search it, there was crime scene tape across the doorway stuck to the frame on each side, and he pulled it off of one side before picking the lock to enter the room. However, he did not bother to stick the tape back up on the outside of the door frame after he entered the room and before closing the door. Someone with his special training would not have made that oversight. Putting the tape back up would be a necessary precaution so that nobody would notice anyone had entered the sealed room, especially while he was in it.