It took Jack Kerouac just three weeks to write what became one of the most influential books of the 20th century, inspiring a generation of writers, artists and musicians from Bob Dylan to Hanif Kureishi.

Or such is the myth. In fact what became On the Road was edited extensively over a six-year period before it was published in 1957. The semi-autobiographical story of Kerouac's American road trips was also heavily censored with explicit scenes of gay sex and drug-taking removed.

Now, however, to mark its 50th anniversary, the beatnik classic is to be published for the first time in its original uncensored form as Kerouac intended.

The new edition will also give Kerouac's fellow travellers, the writers Allen Ginsberg and William Burroughs, and his muse Neal Cassady, their real names instead of the pseudonyms that generations of fans have had to decode.

"It's one step closer to how Kerouac would have wanted it," said Marcella Edwards, head of Penguin Classics, which is publishing the book. "A whole myth has grown up around the book and the road trip across America. This is the unexpurgated stream of consciousness."

Ever since the book was published, giving birth to the beatnik movement and liberating writers and artists to create spontaneously from a stream of consciousness, critics have argued over its literary merits. The American author Truman Capote famously quipped: "That's not writing, that's typing."

But the writer Hanif Kureishi credited the book with changing "the way I saw the world, making me yearn for fresh experience".

There is no doubting its impact, however. More than five million copies have been sold and it remains one of Penguin's best-selling classics. Fuelled by coffee, Kerouac produced the text in a frenzied burst of creative activity over three weeks in April 1951. By taping sheets of paper together, he fed the 120ft-long scroll through his typewriter and wrote, single-spaced with no margins or paragraph breaks.

Adam Freudenheim, a publisher for Penguin, added: "The decision came from the estate rather than from us. I think they had not wanted to publish it for many years because they thought that it might reflect badly on the work of Kerouac. But as it's 50 years since the book was published and nearly 40 years since his death, his estate realised it was time to finally let the world see it. Also, because the original scroll has been touring the world recently, I think it was in their interest to make it publicly available."

A Hollywood film of On the Road is also under way, produced by Francis Ford Coppola and directed by The Motorcycle Diaries director Walter Salles. Carolyn Cassady, who features in the book and who had an affair with Kerouac in the 1950s, is the last surviving member of his circle. Now 84, Ms Cassady said yesterday from her home in Berkshire: "Jack was a warm and kind man – and very romantic, too. But he always said he was the great 'rememberer' – but only if he had written his thoughts down in a little notebook.

"In On the Road he said that I was 'picked up in a bar and taken to a hotel and that's how Neal [Cassady] met me'. But I've never been to a bar by myself – which is something I take umbrage over." She added that Kirsten Dunst has been lined up to play her character in the film.

Along with the touring of the original scroll and a series of readings, the comedian Russell Brand will retrace Kerouac's journey for the BBC. "I'm a fan of Kerouac – not in a thorough and academic way, more inspired by the idea of Kerouac and the style and what he represents," he said.

"So my Radio 2 colleague, Matt Morgan, and I are going to re-create Cassady and Kerouac's adventures. We're going to meet some of the surviving beat poets; we'll go to places of significance, take long car journeys and, you know, just hang out."

Further reading: 'On the Road: The Original Scroll' by Jack Kerouac, published by Penguin Books, 5 September

Kerouac and Cassady on the road – uncut

Published version: Warning him first that he had once been a hustler in his youth, Dean asked him how much money he had. I was in the bathroom. The fag became extremely sullen and I think suspicious of Dean's motives, turned over no money...

Uncensored version: Warning him first that he had once been a hustler in his youth, Neal proceeded to handle the fag like a woman, tipping him over legs in the air and all and gave him a monstrous huge banging. I was so nonplussed all I could do was sit and stare from my corner. After all that trouble, the fag turned no money over to us...

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