The relationship between David Lean and Alec Guinness deteriorated during the making of the movie. The final straw came for Guinness when he found out that a large chunk of his scenes had been left on the cutting floor by Lean. Neither man ever met or spoke to the other again.
David Lean did not have a good relationship with most of the cast. Judy Davis told Lean "You can't fucking well direct" and claimed he didn't understand women. Victor Banerjee argued with Lean over Aziz's accent, calling him "obnoxious" and a hack compared to Satyajit Ray. Peggy Ashcroft disliked Lean's altering the novel and "lack of respect" for her co-stars.
As well as some cast members, David Lean steadily alienated most of the heads of department and their crew during production. The situation on set deteriorated to such an extent that the producer John Brabourne had to order the camera crew to at least say "good morning" to Lean each day.
Satyajit Ray, who had hoped to direct his adaptation of the book, recommended Victor Banerjee for the role of Dr Aziz. After some hesitation, David Lean cast Banerjee, but the director had to overcome the restrictions of British equity to employ an Indian actor. Lean got his way, and the casting made headlines in India. "It was a matter of national pride that an Indian was cast instead of an Asian from England," observed Banerjee.
David Lean cast Judy Davis after a two-hour meeting. When Davis gave her interpretation of what happened in the caves - "She can't cope with her own sexuality, she just freaks out" - Lean said that the part was hers.
The initial script by Santha Rama Rau pleased neither the producer, John Brabourne, nor David Lean. They considered it too worldly and literary, the work of a playwright, and unsuitable for a film. Most of the scenes took place indoors and in offices while Lean had in mind to film outdoor as much as possible. With India in the title of the film, he reasoned, audiences would expect to see many scenes filmed of the Indian landscape. Lean commented: "We are blessed with a fine movie title, A Passage to India. But it has built in danger; it holds out such a promise. The very mention of India conjures up high expectations. It has sweep and size and is very romantic". Lean did not want to present a poor man's India when for the same amount of money he could show the country's visual richness.
During 1982, David Lean worked on the script. He spent six months in New Delhi, to have a close feeling of the country while writing. As he could not stay longer than that for tax reasons, then he moved to Zurich for three months finishing it there. Following the same method he had employed with Great Expectations (1946), he went through his copy of the novel, picking out the episodes that were indispensable and passing over those that did not advance the plot. Lean typed out the whole screenplay himself correcting it as he went along, following the principle that scripts are not written, but rewritten.
When she was in her 50s, Peggy Ashcroft attended the last performance of the theatrical version of "A Passage to India" and met E.M. Forster. He told her that one day she would play Mrs. Moore, something she thought very unlikely at the time because she was so much younger than the character.
Peggy Ashcroft was initially reluctant to take the role of Mrs. Moore. She told David Lean, "Mr Lean, I'm 75-years-old". "So am I," he replied. Although she had recently worked in India on The Jewel in the Crown (1984), she said, "I thought, 'Oh dear, I really don't want to do it', but it's very difficult to turn down a Lean film."
The Marabar Caves are based on the Barabar Caves, some 35 km north of Gaya. David Lean visited the caves during pre-production, and found them flat and unattractive; concerns about bandits were also prevalent. Instead he used the hills of Savandurga and Ramadevarabetta some tens of kilometers from Bangalore, where much of the principal film took place, small cave entrances were created by the production company.
The contract stipulated that Santha Rama Rau would write the screenplay. She had met with E.M. Forster; had successfully adapted A Passage to India as a play; and the author had charged her with preserving the spirit of the novel. However, David Lean was determined to exercise input in the writing process. He met with Santha Rama Rau in Berkeley, Gloucestershire, and over ten days they talked about the novel and discussed the script.
The first David Lean film not made in an ultra widescreen process since Summertime (1955), and only the second one to premiere in the age of multiplex cinemas (Ryan's Daughter (1970) was the first). The Bridge on the River Kwai (1957) was made in Cinemascope, Lawrence of Arabia (1962) in Super Panavision 70, and Doctor Zhivago (1965) in Panavision. Both "Lawrence" and "Zhivago" were shown in 70mm at their world premieres, and all three films had aspect ratios wider than that of "A Passage to India".