Both the stars have subsequently played the title character of Doctor Who: Paul McGann played the Eighth Doctor, and Richard E. Grant the Ninth Doctor from the animated episode Scream of the Shalka. It's also worth mentioning that Richard E. Grant also played the Doctor in the classic non-canon special Doctor Who: The Curse of Fatal Death. He becomes the Doctor upon the death of Rowan Atkinson, and regenerates into Jim Broadbent. Much later, Richard E. Grant eventually appears within the New Series' Eleventh Doctor's tenure as Dr. Simeon/The Great Intelligence. Finally, according to later interviews by Andrew Cartmel, had Doctor Who not been cancelled after the 1989 season, the film's third major actor, Richard Griffiths, would have been offered the part of the Eighth Doctor (after having previously been considered for the part of the Seventh).
Paul McGann's character is not named in the film, although the script gives his surname as "Marwood". There is Lady Mondegreenfanon that his first name is "Peter", as many fans have independently and distinctly misheard, "He's just had an audition for rep," as "Peter's just had an audition for rep."
A very famous version is for the audience to match Withnail drink-for-drink over the course of the film. This means nine and a half glasses of red wine, half a pint of cider, one shot of lighter fluid (contestants are generally allowed to substitute another clear spirit, or vinegar), two and a half shots of gin, six glasses of sherry, thirteen glasses of whisky and half a pint of ale, and one Camberwell Carrotnote A doobie, though, as we would never encourage illegal drug use (unless you live in Colorado), a cigarette is a common substitute. And a hangover the size of Norway, or probably death from alcohol poisoning. It is incredibly difficult to progress far beyond the whiskey Withnail drinks late in the First Act before either violent vomiting, unconsciousness, or sleep kicks in. This is probably a good thing, as the reference to alcohol poisoning was not a joke. The entire shebang amounts to roughly 58 units of alcohol, which is fourteen times the maximum recommended daily intake, just under twice the typical lethal dose for an adult male, and three times the weekly intake levels set by the UK Health Board. The film's running time is 107 minutes...note A wiser version is to pour a single glass of each of Withnail's drinks, plus vinegar, plus cigarette, and take a sip when he drinks.
The first drink consumed on screen is supposed to be lighter fluid. Vinegar was used in the filming (although it was water in the rehearsals), and the reaction of Richard E. Grant (who's actually teetotal in Real Life) was genuine.
Further to the Enforced Method Acting, the director insisted on getting Richard E. Grant utterly plastered with him before shooting started. Grant, who's teetotal due to not breaking alcohol down properly, got utterly plastered and, as Robinson put it, finally knew what it was like to be that drunk.
Irony as She Is Cast: Richard E. Grant is physically incapable of drinking alcohol, due to his body not producing a certain enzyme that forces him to throw any up minutes later.
Memetic Mutation: The film is a virus that attacks the receptive mind, usually male and/or in higher education, leading to groups of people in pubs quoting the script at each other.
Reality Subtext: Something that makes the last twenty minutes even sadder. At the time, Paul McGann was an established actor and so he knew that he was still having a career after this movie. This was Richard E. Grant's first movie, however, so he had no idea if this was going to his one and only film or not and so he knew how upset and jealous Withnail was feeling. But as we all know, Grant's fears were unfounded and this film even managed to make him a sex symbol for a while.
Robinson based Withnail on his Real Life friend and actor, Vivian MacKerrell who actually did drink lighter fluid once. Robinson has attributed his friend's early death from throat cancer to this incident.
Take That: As mentioned below, Bruce Robinson alleges Franco Zeffirelli pursued him at one time. During an early scene in the film, Withnail reads a newspaper headline of "Boy Lands Plum Role For Top Italian Director," and goes on to suggest the reason the actor has the part is the director's amorous interest in him.
Write Who You Know: The film is based on Robinson's own life in London, albeit dramatized and condensed a bit. Withnail is based on his friend Vivian MacKerrell, who later died of throat cancer.
Robinson maintains he received unwanted advances from Italian filmmaker Franco Zeffirelli whilst playing Benvolio as a young actor in the 1968 film adaptation of Romeo and Juliet. Uncle Monty is loosely based on this experience.