On the morning of 9 April 1940, German forces occupied Denmark and invaded Norway, leaving Sweden as the only neutral country in Scandinavia. It was to this country, surrounded by Axis forces, that Captain H. M. Denham was posted as Naval Attach?, arriving after evading capture by the Nazi Wehrmacht in the summer of 1940. Over the course of the next five years Captain Denham used his position to covertly provide valuable intelligence...