Highly Dangerous is a rare original screenplay by novelist Eric Ambler. It draws heavily on elements of his early pre-1939 thrillers, but reposts them behind the Iron Curtain. This film leans particularly on Ambler's first novel The Dark Frontier, most notably with the super-agent coda, which is very fashionable today.
Ambler's problem with Highly Dangerous is that most of the plot devices he invented single-handedly in the 30's were used to the point of saturation by film-makers during the 40's. By the time he got around to an original screenplay it all seems very unoriginal. For that reason I like to think of this film as British cinema's homage to all Ambler's great work in the 30's. An adaptation of one of Ambler's post war novels, say, Judgement On Deltchev, would have been much more satisfactory at this point in his career - as it was, he had to wait ten years until Topkapi before the cinema recognised his post-war novels.
Margaret Lockwood makes for a very beautiful and personable innocent, drawn into a cold-war plot about a form of biological warfare, not entirely a new thing, but a change from the nuclear threats of the time. Lockwood's career was on the decline, and this film can't have offered her very much compensation. Additionally, she is badly served by her make-up artist, her hair being mocked up to middle-age very badly.
Don't treat this film as a serious attempt to translate Ambler's art to the screen - you can find that in just about any war-time thriller - from Journey Into Fear to The Mask of Dimitrios. Highly Dangerous is minor Ambler, and an opportunity for a fading Lockwood to make one more impression, and what an impression - innocent, scientist and secret agent.
