The series was beset by sound quality issues, prompting complaints from viewers that the dialogue was inaudible.
In the late 1970s, copies of Len Deighton's book carried a "Soon to be a major motion picture" sticker. In 1978, famed exploitation producer Harry Alan Towers had set this up as a British -Canadian co-production to star James Mason, Ralph Richardson, Kate Nelligan and Rod Steiger, but financing fell through at the last moment.
In actual history, the British atom weapon program was one of several scientific projects transferred to the USA when they joined the war. Historians believe that it was British work rather than Albert Einstein's famous Letter from Long Island that caused the vast investment made in the Manhattan Project.
In actual history, it was two refugee Jewish scientists in Britain who made the key breakthrough. The Frisch-Peierls memorandum of March 1940 revealed that a nuclear weapon could be made with about a kilogram of material rather than several tons, as most people then believed . Neither [scientist] is mentioned, but the circulating documents might be a development of their work.
For German television, the original 5 episodes were re-edited into 6 episodes.