“I follow Carl’s life and career, but my goal was to be true to his spirit, not his shirt size,” explains Smith, giving some hint of the humour he has brought to bear on a tale of struggle and heroism. “Everyone wanted the script to resonate as much as possible so, as a dramatist, I sometimes took it up a level.”

Smith didn’t come across the story of Brashear all on his own, however: it was Bill Cosby who first decided that it would make a great movie. The first African-American to become a Master Diver in the US Navy, Brashear overcame enormous odds at a time when the Navy was officially desegregated, but when African-Americans rarely rose above the status of cook.

Wary of, on the one hand, not doing the story justice and, on the other, turning it into an educational tract, Cosby and his production partner, Stanley Robertson, interviewed a whole series of writers to see what angles they might adopt. Smith got the job.

“They heard pitches on doing Carl’s story as everything from a gangster picture to a musical,” recalls the young writer, whose day-job at the time was director of marketing for Panavision Hollywood. “I saw it more as a classic drama of the fifties. My job was to elevate the level of drama that was already evident in Carl’s life.”

In Smith’s ‘elevated’ version, Brashear (played in the movie by Cuba Gooding Jr), starts out as the son of a Tennessee dirt farmer, whose major piece of advice to his son is “Never quit: be the best”. That and “Don’t end up like me”. With this in mind, Brashear enlists in the Navy just after World War II. Sure enough, he soon finds himself flipping burgers below deck. But his first tour of duty allows him to catch a brief glimpse of the mysterious world of the deep-sea diver when he sees Billy Sunday (Robert De Niro) disobey orders to rescue one of his men.

Brashear - an extremely strong swimmer with the ability to hold his breath for over four minutes - is determined that deep-sea diving is where his career is headed. But it takes him two years of submitting applications to the Navy Diver School at Bayonne, New Jersey, before he is finally accepted.

That, however, is only the start of his problems. As presided over by a reactionary old commanding officer known as Pappy (Hal Holbrook) and run with an iron hand by the same Billy Sunday, Bayonne doesn’t exactly throw open its doors to African-Americans. Indeed, all the other recruits with a single exception - a Wisconsin farm boy with a speech impediment called Snowhill (Michael Rapaport) - refuse to share their barracks with “a nigger”.

Overcoming his lack of schooling with the help of a local librarian called Jo (Aunjanue Ellis), who later becomes his wife, and outperforming all the other trainees, Carl nevertheless almost fails to graduate. Pappy, stating that there will be no black divers in the US Navy as long as he is in uniform, gives Billy a direct order to fail Brashear. Finally convinced by Carl’s bravery (he spends eight hours in freezing water, overcoming all the obstacles deliberately placed in his path), Billy disobeys orders, however, and Carl graduates. But it is a path of action which leads to Billy being busted from Master Chief (the highest rank an enlisted man can obtain) and reassigned.