With lots of solid acting and believable characters, this 'loosely' based on adaptation of the book is still better than lots of other spy stories from this period. What makes it unique is that the central (and real person it's based on) is female and that she was only exposed late in life. Another successful rendition of a period piece which the British do so well for the most part. The performances are largely spot on, apart from a few roles that didn't ring true and felt 'thin', like the 'Canadians' (I am one). But there's enough intrigue and tension and historical truths that it keeps your attention throughout. The pace is just right and although a few minor scenarios were not that interesting or even necessary to the story, the overall writing and dialogue felt very authentic. Beautiful cinematography and thankfully the background music stayed subtle (unlike most shows these days), and the period details also caught the mood and look of the times depicted. Not the best spy movie ever made but one of the better ones.
