You're thinking of Thunderball.
Before Dr No was produced, a producer called Kevin McClory approached Fleming with the idea of doing a Bond film but an original story not an adaptation. McClory and Fleming came up with a storyline which was then turned in a script by Jack Whittingham. For a variety of reasons the film never got made. Not wanting to waste the time he had spent on the project, Fleming took the story line and reworked into the novel Thunderball.
If you look at the credits for the film of Thunderball you will see that they read
Screenplay by Richard Maibaum and John Hopkins, based on an original story by Kevin McClory, Jack Whittigham and Ian Fleming.
McClory even claims that he created SPECTRE and Blofeld.