When I looked up information about this film on IMDB, I realized that writer/director Val Guest was also one of the ones responsible for the god-awful "Casino Royale" (1967), a disjointed and unfunny from start to finish. And, as this ALSO is a spy film I assumed it would be terrible. However, the film ended up being the total opposite of his later fiasco...as the spy in this one was much more realistic (for good as well as bad).
The Irish actor, Stephen Boyd, stars in this as a British spy. You really don't know much about who he works for and if he's even one of the good guys for much of the story. Instead, the first portion focuses mostly on his vacation in the Alps and the time he spends with a pretty Swedish woman. Only later does the spy aspect of the film occur...and some rival group wants to get information out of him...or kill him.
The film has a lot of mediocre reviews and I can understand this. The story is NOT packed with action and excitement and seems to emphasize realism instead. And, I can only assume real spies are a bit dull most of the time! But I appreciated this realism and thought the film worth seeing.