Although the movie is based on a true story, it has been indicated by Billy Hayes himself 20 years after its release, that what is presented in the movie is a very exaggerated version of what happened to him in the prison in Istanbul, Turkey.
The scene in which Brad Davis' character bites out the tongue of a fellow inmate upset the crew so much that they all walked off the set, leaving Alan Parker to shoot it with his two actors. For the scene, Davis carried a pig's tongue around in his mouth.
Oliver Stone's original script detailed Billy Hayes' escape over the mountains, but the the small budget did not allow for the filming of these scenes. The actual escape that occurred in real-life was not used for the movie, replaced with a different escape. The escape in the film was shot in Greece doubling for Turkey.
The large group of Turkish police and soldiers at the Istanbul airport, which are on hand to search each passenger before they board the jet, was another attempt by the film makers to portray Turkey as an authoritarian police state. But in reality, this real-life event that Billy Hayes encountered of a thorough search of each passenger was a reaction to the PLO hijacking (and subsequent destruction) of four passenger jets in Europe just four weeks prior to the event portrayed at the beginning of the film (October 6, 1970). There are two somewhat oblique references to this event early in the film: a headline on the paper that Susan is reading on the bus that takes them to the plane ("Nixon Outraged at Palestinian Hijackers"), and again in the car after his arrest when Tex says "You decided to fly at a bad time... guerrillas all over the place, blowing' up planes... 4 planes in 4 days".
Producer David Puttnam has mixed feelings about this project. He was happy with the finished cut but when he saw the film with a paying audience at a late night showing in New York, he was deeply disturbed by the audience's reaction to some scenes. They were cheering and clapping instead of the desired effect of being repulsed by the characters actions.
Billy Hayes visited the Maltese filming locations during principal photography exactly two years to the date he had escaped. Hayes said: "It was so true to life that I started to sweat. It was obvious to me that everyone concerned wanted to make a film that says something - and there's a lot to be said . . . Hopefully, we can shake people up, and move them to do something for all those others who are still locked up in stinking hell-holes around the world".
In a scene at the airport, the middle-aged Turkish customs officer (played by Joe Zammit Cordina) supposedly speaks Turkish to Billy. However in reality, he is speaking Maltese after he forgot his lines in Turkish and he decided to use his native Maltese on the spur of the moment. The only Turkish words he speaks are 'pasaport' (passport) and 'cantayI' (bag).
Publicity for this picture told of the start of the letter that Billy Hayes wrote to his parents in 1970. It read: "Dear Mum and Dad, This is the hardest letter I've ever had to write. I know the confusion and the pain it will cause you, and the disappointment.....I was arrested at Istanbul Airport yesterday, attempting to board an airplane with a small amount of hashish.....".
Prior to principal photography, director Alan Parker wrote a letter to the cast and crew. Publicity for the picture reproduced it. It said: "Firstly to say something before we start. Secondly, to warn you about a very difficult film. And thirdly, because I heard Ingmar Bergman always did it! As you have gathered from the script, it is my intention to make a very violent, uncompromisingly brutal film, the subject matter of which will no doubt take its toll on us all. This is not just a boring prison story set in claustrophobic cells and corridors. It's much, much more than that - a prison no one's ever seen before...It's difficult to put into words, but I would like the audience to be shaken and shocked that such things happen, almost to the point of disbelief - but never to lose them".
Billy Hayes' speech in the courtroom scene in the film went longer than it did in real life. In it, Billy gives a long soliloquy against the Turkish penal system and according to Hayes, said everything he wish he had said in the dock.
To find a suitable prison for filming, location scouts were conducted in Crete, Cyprus, France, Israel, Italy, Sicily, Spain and Malta, the latter country being successful with Fort St Elmo which got to double for Istanbul, Turkey's Sagmalcilar Prison. The fort was the site of the legendary Great Siege of Malta in 1565. The original Turkish gaol could not be used for self-explanatory reasons.
Director Alan Parker once said that this film was "the first story which could be made in Europe with a British crew and had a chance of making it in the States. It's an American story; it doesn't compromise; and it's the opposite to what I've done before".
The first director Oliver Stone approached with his script was Michael Cimino. Cimino has said that, though he loved the script, he had to pass as he was about to begin shooting his passion project, The Deer Hunter (1978). Both films wound up being nominated for best director and best picture at the 51st Academy Awards in 1979; Cimino wound up winning in both categories. Regardless, Cimino developed a good relationship with Stone, and the pair would later work on Year of the Dragon (1985) together.
Author Mary Lee Settle's says in her book "Turkish Reflections" (1991) that "The Turks I saw in Lawrence of Arabia (1962) and Midnight Express (1978) were like cartoon caricatures, compared to the people I had known and lived among for three of the happiest years of my life".
At the end of the movie, Billy Hayes killed the head guard, Hamidou, by pushing him into a clothes rack and impaling him. In real life, it wasn't Billy Hayes that killed the head guard but a recently paroled prisoner, where he spotted Hamidou drinking tea at a café outside and shot him eight times, killing him.