Re: Book recommendation: Most secret war
And the TV series "The Secret War". narrated by William Woollard. It was that series, broadcast in early 1977, that spawned said book (1978). Available on DVD.
It was also this book and TV series that brought the story of Enigma, Colossus et al into broader public knowledge, notwithstanding Winterbotham's earlier book (1974). RV Jones was much more accurate, too (having been at the centre of it all)