Filming stopped when finances dried up and star Laurence Harvey died. According to Peter Bogdanovich, the only portion of the film not completed was an explosion toward the end of the story. Later part of Jeanne Moreau's dialog was lost but she was never asked to rerecord it. Currently the film exists in a work print held by the Munich Filmmuseum, which reportedly is now looking into the possibility of new footage being held privately in France.
Unfinished.
Although the production was deeply troubled, many of the people involved have spoken highly of the film, including lead Jeanne Moreau, who in 2000 looked back on the film as "a fantastic experience", noting that "the only disastrous thing was that later on, the film disappeared."
Orson Welles intended the film to be a less personal, more commercially viable project than his past efforts, saying, "My hope is that it won't be an art-house movie. I hope it's the kind of movie I enjoy seeing myself. I felt it was high time to show that we could make some money." Peter O'Toole recalled that he was approached by Welles to play the lead in the film and remembered The Deep as "a script that I thought was beautiful."
Orson Welles struggled to finish the film after production effectively halted in 1969. He edited trailers and short scenes to help secure financing, and at one point contacted Charlton Heston about recording voice-over narration.