During the shooting of the movie Paramount sent a telegram to producers in Africa to immediately fire Michael Caine because they had seen the rushes and decided that he was giving a terrible performance. Caine read that telegram before the producers, because the secretary gave him to read it. Afterwards he was very nervous waiting to be fired and he couldn't mention this to the producers because he would get that secretary into trouble. After a few days he mentioned it to one of the producers, making up a story of how he read the telegram. The producer told him he wasn't fired - and warned him to keep away from his mail.
In real life, both Chard and Bromhead were considered less than remarkable officers by their superiors and were overage (Chard was 32 and Bromhead 33) for their rather junior rank of Lieutenant. The defense of Rorke's Drift galvanized their careers with Chard ending as a Colonel at the time of his death (of cancer at 49) and Bromhead reaching Major before succumbing to typhoid at 46.
In real life, Lt. Bromhead, played by Michael Caine as an arrogant "upper class twit", was extremely deaf. It was much more for this reason - rather than the few months' precedence in gaining his commission which Chard (Stanley Baker) claims in the movie - that Bromhead agreed to relinquish command. Chard's precedence, historically, was closer to three years than to the much more dramatic matter of months.
In real life, Pvt. Henry Hook (played by James Booth) was nothing like the hard-drinking, insubordinate, malingering malcontent portrayed in this film. In fact, Hook was never a discipline problem and was known among his fellow soldiers as somewhat of a prude.
In the real battle for Rorke's Drift on which this film was based, only 17 British soldiers were actually killed.
Several years ago Michael Caine aired a one-man show. He stated that when he finished his audition he was rejected for the part. A few months later he was attending a cocktail party where the producer was also attending. The producer asked him if he still wanted the part, and Cane reminded him that his audition was considered "terrible". The producer replied that the original actor took very ill and the crew was leaving from Heathrow the next morning. Caine shook the producer's hand, left the party and went home to pack his bags.
Still Photographer Bob Martin and Nigel Green visited the Zulu war museum in Ladismith and found a Queen Victoria commemorative silk handkerchief on which was printed, "Bugle calls to be used in battle". Green got permission to copy these "notes" after practicing for weeks ("I had not blown a bugle since my navy days years before") and, armed with the prop bugle, Claude Hitchcock and the sound crew recorded the calls in a gorge (for echo effect) they were used in the final soundtrack of the film.
The 700+ Zulu extras were largely descendants of the actual warriors who took part in the battle, among them the then chief of the Zulu Nation, Chief Mangosuthu Buthelezi, taking the role of his predecessor, Cetawayo.
The Epilogue, narrated by Richard Burton, states that 11 soldiers from the battle were awarded the Victoria Cross, which is correct. However, 12 soldiers were actually nominated for the award--the 12th being color sergeant Frank Bourne (played in the film by Nigel Green). On being informed of his nomination he requested that he be given a commission instead, which the army agreed to do, awarding him instead with the Distinguished Service Medal. Bourne was the youngest color sergeant in the British Army at the time and went on to have a distinguished career, retiring as a Lieutenant Colonel. When Bourne died in 1945 he was the last surviving British soldier from the battle.
The film was shot in the Royal Natal National Park, which is about 90 miles southwest of Rorke's Drift (the Amphitheater mountain forms a dramatic backdrop in the movie). The area surrounding the actual Rorke's Drift is nowhere near as mountainous as in the film.
The opening and closing narration is read by Richard Burton.
The rifles in the film are Martini-Henry single-shots in .450/577 caliber. The weapons seen in the film are period-correct short lever versions (the design was modified in the 1880s with a longer lever to aid extraction.
The then Minister of Native Affairs banned the film for screenings to black South Africans as "it might incite them to rise up in revolt".
This was Michael Caine's first major film role. He watched the rushes, but was so nervous that he was sick, and never watched rushes again.