Sir Michael Caine and author Frederick Forsyth had been friends for around ten years prior to this movie. In the three earlier filmed adaptations of Forsyth novels, Caine was never selected to be in them. So the two decided to raise the financing themselves, so as to make sure they could work on a movie together. The two are billed as executive producers on this movie.
The Fourth Protocol is a fictional secret protocol of the 1968 Nuclear Non-Proliferation Treaty, containing an agreement between nuclear powers that nuclear weapons will only be delivered to their target by conventional means (dropped from aircraft or on missiles). In the world of this movie, it effectively prevents them being left in luggage lockers or delivered by postal companies or other clandestine means.
Sir Michael Caine once said of this movie in his autobiography "What's It All About?" (1992): "We wound up with a wordy action movie which, although it was quite a good picture, and did fair business, never had the speed and pace of the best American action movies. So for long sequences in the film, we not only had a talking picture, but a lot of talk, and even worse, most of it unintelligible. I went there as the star and associate producer, and one might have thought this would give me sufficient authority to put my own strongly-held opinions into practice, but no chance. Even I, in my exalted position, wound up making a talking picture, when it should have been a moving one."
"The Fourth Protocol" was the fifth novel and seventh book written by Frederick Forsyth. An instant hit world wide selling over 7 and 1/2 million copies with the author being swamped for the film rights.
The Radio Moscow presenter reading the news broadcast to which Valeri Petrofsky (Pierce Brosnan) is listening for information was Frederick Forsyth.