Philip Marlowe, the quintessential hard-boiled private detective, is Raymond Chandler’s greatest creation. First appearing in The Big Sleep 80 years ago, Marlowe – a tough-talking, trench-coated detective – may now read like a cliche, but he was the first in a line of lesser imitators, and is wonderfully of his time. He spins whiskey-soaked philosophies as easily as he throws punches, growls the labels “broad” and “dame” as casually as he slaps the occasional femme fatale, and falls into bouts of love and melancholy that reveal the vulnerability behind the machine gun.

Irish writer John Banville, who writes crime under the pen name Benjamin Black, has always been a fan of Chandler and his complex creation. But when he was asked by the Chandler estate to write a new Marlowe thriller in the voice of an author he calls “inimitable” he was initially apprehensive. At a Guardian Live event on Thursday 5 February, Banville shared some of the realisations he’d had when stepping into Chandler’s shoes.

1. Four-letter words and romancing birds? Out of the question

Apart from the occasional snarled “damn”, Marlowe’s mouth is soap-scrubbed by today’s standards. “I thought we’d have to include four-letter words but there is a lot of style in Chandler obeying the rules of his time, the rules of decency,” Banville said. “I thought it would be good to hold to these laws – and it was both interesting and limiting.”

Same for sex: Chandler always left Marlowe’s romantic interludes implied. Banville compares this fondly to the fade-to-black technique used in old Hollywood films during intense romantic scenes. “It’s much more convincing than a couple of actors climbing on each other, like we have these days. The way actors kiss now... I have a friend who calls it ‘Hollywood face-fucking’. I had to keep Chandler’s formula, the one the fifties imposed on him. It had to stay chaste.”

2. No Sherlockian reboot: Marlowe had to stay in 1950s LA

Banville revealed he had briefly considered writing Marlowe into a modern setting, but realised he had to stay in his time. “It’d be like making Bertie Wooster a clubber,” he said. “For noir fiction, the fifties are a wonderful period, but it was mean and poverty-stricken, spiritually as well as financially. I was a child in the fifties and it was awful, but to write about it now is fascinating.”

Like Banville, Chandler was not native to Los Angeles, Marlowe’s home turf: he was born in Chicago, educated in England and didn’t move to California until he was in his fifties. “But Los Angeles is a love object for Chandler,” Banville said. “He conjures up Los Angeles almost without writing about it. You feel the heat, that strange humid climate, [you] see the palm trees coming off the page.”

3. If you’re going to rewrite a character, don’t reread the books

Rebooting an iconic character was one thing, but rereading his adventures is another. “Oh god, no,” Banville exclaimed when asked if he reread Chandler’s back catalogue before starting. “I wanted to write the spirit of Chandler, not to parrot. I went back and made a couple of notes, but I didn’t read them all. The worst thing you could do is make a list [of Chandler’s quirks] because it would become mechanical.” He went on to write The Black Eyed Blonde in a single summer, a process he doesn’t remember because he was “in a state of self-hypnosis”.

There are differences between Banville’s Marlowe and Chandler’s: Banville has less enthusiasm for peppering paragraphs with countless similes – “You know he was writing hungover in some of those” – and is light on fights. “My Marlowe is probably more melancholy, less tough. Every now and then you can see where Chandler says: ‘Oh, I have to get him beaten up or have him beat someone up now.’ But Marlowe is at his best when he is trying to better himself.”

4. Private dick Philip Marlowe: “a knight out of Arthurian legend”?

Philip Marlowe is not only a damn swell detective: he’s “the closest we’ve come in recent fiction to Arthurian legend, the lone knight,” said Banville.

“I think popular fiction does have a duty to not be totally nihilistic. I think it should present a moral character,” added Banville. “Marlowe says: ‘Despite being a screwed up drunk, I have to live as well as I can.’ And I think he does. We all need something to cherish. Chandler had his cats – Marlowe doesn’t even have a cat! He only has this sense of himself, as a decent human being. Surrounded by these corrupt, sad people, he is the knight on his horse showing the way. But inside that suit of armour is a shivering human being, no better than anyone else – maybe worse.”

5. Thank F Scott Fitzgerald for Raymond Chandler

Banville attributes the greatness of multiple American novelists in Chandler’s era to one man: F Scott Fitzgerald. “The Great Gatsby was the great challenge to American writers – John Updike, Norman Mailer, even Chandler. Fitzgerald was the ultimate romantic - with a lower case ‘r’, which is the best kind. In all his works he was saying that, for all the speed and violence of American life, there is a romance to it.”

The best Marlowe adventure, in Banville’s eyes, is The Lady in the Lake: “[It’s] a very strange book, no wise cracks and a lot of unhappiness, but it is his best, technically.” His favourite, however, “by a long mile”, is The Long Goodbye. “It is his most deeply felt book, the most Gatsby-esque. It is all over the place, though,” he said. “The twist, when Terry Lennox returns, disguised with plastic surgery, shouldn’t have been done. Now, that was a hangover morning for Chandler.”

Guardian Book Club: John Banville on Philip Marlowe took place at the Guardian offices, London on 5 February 2015.

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