For years, student union bars have resounded to such memorable lines as "I demand to have some booze" and "Officer, I've only had a few ales", as generations of students attempt to match the characters' prolific alcohol intake drink for drink.
But if the film's creator has its way, Withnail & I will never appear on the West End stage.
Bruce Robinson, the writer and director of the classic 1987 movie, starring Richard E Grant and Paul McGann as two "resting" actors in 1969 London who take an alcohol-fuelled trip to the country, has described plans for a stage version, potentially starring Jude Law, as "scandalous".
He insists that Hand Made Films, the production company that made Withnail & I, needs his permission to go ahead with a theatrical production, which he refuses to grant. Hand Made Films, set up by George Harrison in the 1970s, maintains it owns the necessary rights to turn the film into a play.
"It's scandalous," said Robinson, who says he has still not received his full director's fee nearly 20 years after the film was made. "The film of Withnail & I that I wrote and directed is what I wanted to say. Anything ancillary to that seems to be an attempt to wring it out like an old teabag for more money."
A spokeswoman for Hand Made Films said: "Hand Made own the copyright and the rights to Withnail & I. Bruce Robinson, who was one of the writers, does not own the rights or the copyright. However, it is normal to seek creative approval from one of the writers, and that process is under way. Everything is on track."
Robinson said that at a meeting with his agent and lawyer in Los Angeles last week, Hand Made's chairman, Patrick Meehan, accepted that a stage production could not go ahead without the writer's agreement.
"He does not have the contractual rights to putWithnail & I on in the West End or the Outer Hebrides. He would have the right to put on the play in the West End providing he had my agreement, in the same way as I could put it on if I had his agreement."
Hand Made said nothing was settled at the meeting, adding that "lawyers and agents are working on it".
However, Robinson denied saying that Jude Law would not be able to do justice to the part of Withnail. "Whatever my feelings are about Jude Law, it's completely hypothetical, because this isn't going to happen. This chap Patrick Meehan can't put Withnail & I on the stage, period."
In contrast, Grant, who plays the film's louche hero Withnail, believes a stage production is a good idea. He said: "Good luck to them. I think the idea would transfer to the stage very well, and of course Bruce's original was such a brilliantly written script that I'm sure the part would be a success for anybody who tries it." In the movie, Withnail and his friend Peter Marwood, played by McGann, visits his lascivious Uncle Monty's country cottage with hilarious results. It is probably Grant's most memorable performance.
Details of the stage project, which were revealed in financial papers released by Hand Made Films as part of a reverse takeover bid, were revealed by The Independent last month. The "offer document" said Laurence Myers, the producer behind the acclaimed production of Keith Waterhouse's Jeffrey Bernard Is Unwell, would bring Withnail & I to the stage. It stated: "A UK theatrical show of Withnail has been agreed with the London producer Laurence Myers. Production is anticipated for 2007."
Robinson was originally offered £70,000 to direct the comedy he had written. But this upfront payment was cut to £40,000 in order to pay for one of the movie's classic scenes, in which Withnail and Marwood drive back from the country to London and are stopped by the police after partaking of "a few ales".
Where are they now?
Richard E Grant Withnail
Two years after Withnail & I, Grant starred as a stressed-out advertising executive in Bruce Robinson's How To Get Ahead In Advertising. Numerous television and film roles followed, and Grant's autobiographical film, Wah-Wah, which tells the story of his childhood in Swaziland, premiered in London this week.
Paul McGann Peter Marwood
McGann now lives in Bristol with his wife and two children. He appeared in a 1996 television movie revival of Doctor Who and was originally cast as Sharpe in the ITV series, but replaced by Sean Bean after breaking a leg. His latest film, the forthcoming Poppies, is about a man coming to terms with loss.
Richard Griffiths Monty
As Uncle Monty, Griffiths made a pass at a terrified Marwood, saying: "I mean to have you even if it must be burglary". More recently, he has played mean Uncle Vernon in the Harry Potter films, and is currently starring on Broadway as an eccentric teacher in the award-winning Alan Bennett play, The History Boys.
Ralph Brown Danny
As the drug-dealer Danny, Brown created the world's largest spliff, the Camberwell Carrot: "I invented it in Camberwell and it looks like a carrot." Since then, he has played the gangster Miami Vice in the television series based on Guy Ritchie's film Lock, Stock and Two Smoking Barrels, and has appeared in Coronation Street, Spooks and Nighty Night. In the forthcoming Straightheads, he appears alongside Gillian Anderson in a twisted tale of revenge.