This movie was to be the first in a series of spy movies featuring the character Philip Calvert (Sir Anthony Hopkins). Since Sir Sean Connery had stated that he would be doing no further James Bond movies, the producers saw a vacuum in the spy-action genre. However, this movie's box-office failure scrapped any plans for future entries in the "Calvert" series.
According to stuntman Bob Simmons' 1987 book "Nobody Does It Better: My 25 Years of Stunts With James Bond and Other Stories", he helped Sir Anthony Hopkins slim down and prepare for the lead role of Phillip Calvert in this movie, a character who was a frogman, commando, and Royal Naval officer.
The term "Eight bells" is a nautical reference to the hour of midnight. It is also a nautical euphemism indicating "finished" as well as an expression stating the end of a sailor's watch (as in an obituary).
Sir Anthony Hopkins and production secretary Jennifer Lynton met while making this movie and were later married.