It was a film made to remember "those few young men with hope in our hearts and wings on our heels". 

Yet, when Chariots of Fire was released 40 years ago this month, Warner Brothers studio moguls doubted it would be a success.

They needn't have worried. "It's an exceptional film about some exceptional people," enthused Vincent Canby in the New York Times.

"The track sequences, even to one who has no real interest in track, are charged with poetry."

The film told the story of British runners Eric Liddell and Harold Abrahams - both Olympic gold medallists at the Paris 1924 Games.

"I literally stumbled across this story," producer David Puttnam said.

"I had always loved the film A Man for All Seasons. 

"What I loved about it was that important thing in the cinema, the conceit that you would act as he did if you were put in that position. 

"Originally I was looking for a story. Something tangible, that someone would do something extraordinary, but contemporary."

Puttnam found what he was looking for in an Olympic history written by American writer Bill Henry.

"Now it turned out that the book got all sorts of things wrong , but the important thing that he got right was this guy who refused to run in the heats which were run on a Sunday," he said.

The runner in question was Liddell.

"I thought 'boy oh boy, this is exactly it,'" said Puttnam. "I read on and I realised that Harold Abrahams had won that year."

In the film, Liddell was played by Scottish actor Ian Charleson. Ben Cross was cast as Abrahams.

The eminent athletics coach and sports historian Tom McNab had been recruited as "athletics consultant" and also played an important role in selecting the cast. 

"Puttnam said to me, 'we want you to do an audition with them,'" he told insidethegames. "'Only choose the ones you can train as athletes'. None of them had done any sport at all.

"I had about 32 actors at Putney on a cinder track in the middle of the winter. Most of them were sick during the warm-up. They weren't fit in any way.

"I chose Ben and Ian. Puttnam heaved a sigh of relief and said 'those were the ones I'd wanted.'" 

There were other uncredited extras in the film who were not required to do any running. They included Kenneth Branagh, Stephen Fry and future England cricketer Derek Pringle.

The film shows Abrahams arriving in Cambridge, where he joins the operatic society and demonstrates the speed that will ultimately take him to Olympic glory.

Abrahams was from a prominent Jewish family and the film more than hints at prejudice and discrimination.

Sir John Gielgud and Lindsay Anderson play the senior academics at Caius College, Cambridge, who disapprove when Abrahams employs Sam Mussabini, a professional coach, played by Ian Holm.

By the time the film was conceived, Abrahams was 79-years-old and very much an elder statesman of British athletics, but he agreed to offer his advice.

"We started working with Harold, but on the third meeting, we met his coffin," said Puttnam.

Screenwriter Colin Welland attended the memorial service held for Abrahams in London.

"That is why the film begins with the memorial service," he said. "Colin went and that is where he had the idea of starting the film in that way."

The film switches to Scotland to tell the story of Liddell. The son of a missionary, he was born in China and was a devout Christian.

He returned to Scotland to study and also won seven international rugby union caps. Liddell abided by strict amateur rules in force at the time which meant McNab was forced to ask Welland to alter one sequence.

"He was obsessed with Powderhall," McNab said. "He said we could have a sequence with Liddell running at Powderhall?"

Powderhall was a sprint event for professionals and Liddell would have faced an Olympic ban had he taken part.

Instead, McNab suggested a Highland Games sequence.

The producers carefully studied Liddell's running style and his family were invited to a private screening before the film was released.

Puttnam recalled how Liddell's widow Florence told him: "You got one thing wrong. Eric was a beautiful runner." 

"In fact because we had footage of him, we knew he ran with his arms flailing," Puttnam said. "So the only thing we knew we got right was the one thing she thought we'd got wrong."

Liddell's refusal to run on a Sunday was decided long before he travelled to Paris, but the episode was changed in the film for dramatic effect.

McNab recalled: "We have him changing his mind on the boat. That was nonsense but it doesn't matter, the basic principle is that he didn't run on the Sunday. It just didn't occur in that way."

Puttnam agreed. "The interesting thing is you have to make these judgements, where is the greater truth, the greater truth is the importance that they got that medal," he said. "I have never felt for one moment that any of the liberties that we took were wrong. I never felt there were any distortions in the story."

Before the gold medal race, Liddell is shown receiving a note from American Jackson Scholz. The message reads: "It says in the old book, he that honours me, I will honour."

Liddell duly ran to victory. After the Games, he returned to China as a missionary. He was interned during the war and died in 1945.

The production team had worked with his sister Jenny and his family. Puttnam was told that "Eric was never a good speaker and he knew it".

"He never could preach the way he would have loved to. You gave him a voice."

The film's title Chariots of Fire is now synonymous with the Olympics. The title incorporated the words featured in the hymn Jerusalem which is heard at the end of the film. Welland had apparently been inspired by hearing it during a television programme.

As McNab recalled, the working title at the outset was different.

"The film was originally called The Runners," he said. "I've still got a copy of it somewhere."

The original storyline was also different and featured 800 metres champion Douglas Lowe.

"In our first draft, Lowe was quite an important figure and we wrote to him," said Puttnam.

"I got a letter back from what was now his honour Judge Lowe, saying 'how much money do we pay?'

"I wrote what I thought was rather a nice letter saying we are going to make an honorarium of 500 guineas to all involved. He wrote back to say he wanted nothing to do with it.

"The day the film came out, the obituary of Judge Lowe, who had died the previous week, came out in The Times. Half of it was about how proud he would have been to have seen the exploits of his compatriots celebrated. So this man who wouldn't let us use his name or have anything to do with us ended up having half his obituary in The Times usurped by the movie."

McNab had been made aware of  the difficulties with Lowe and advised Welland: "We don't want another gold medallist. That is going to take attention away from the two main characters. Why don't we have a rather dilettante sort of person, a rather aristocratic person and make him something different, a hurdler? Something that I could maybe coach him to do."

The part of a hurdling aristocrat went to Nigel Havers.

It was broadly based on Lord Burghley, Marquess of Exeter, a 1924 competitor in the 110m hurdles who won 400m hurdles gold in 1928.

By the time the film was made, Exeter had just resigned as the head of global athletics but was still a member of the International Olympic Committee.

Puttnam said: "He was very helpful and said he was very happy to involve himself, but didn't want us to use his name, which is why he became Lord Lindsay in the film."

In a memorable sequence, Havers is shown hurdling outside a stately home with a glass of champagne on each hurdle. "If I shed a drop I want to know," he says. "Touch but not spill."

The scene was inspired by Don Finlay, a team-mate of Lord Exeter who had won Olympic bronze in 1932 and silver in 1936.

"Colin had read that Don used to put matchboxes on top of the hurdles," said McNab.

"I said 'that's no good with matchboxes, he's an aristocrat'. He said 'we'll put champagne glasses on.'" 

In fact, as the crew discovered, they did not contain champagne, but what became warm ginger beer.

The film received seven Oscar nominations. It won for best picture, best original screenplay, best costume and best musical score.

The memorable and evocative theme by Vangelis was even adopted by the BBC for their 1984 Olympic coverage.

It was also performed in a special tribute by comedian Rowan Atkinson at the London 2012 Opening Ceremony.

The audience discovered Atkinson sitting with an orchestra. As the music rises, they see that he is daydreaming and focus shifts to the screens where Atkinson is seen on a beach.

The scene from the opening titles was then recreated using computer technology.

Organisers said it was "to honour Britain's cinematic tradition" and the segment honours the film most associated with the Olympics - Chariots of Fire.