Robinson's script is largely autobiographical. "Marwood" is Robinson; "Withnail" is based on Vivian MacKerrell, a friend with whom he shared a Camden house, and "Uncle Monty" is loosely based on Franco Zeffirelli, from whom Robinson received unwanted amorous attentions when he was a young actor.Early in the film, Withnail reads a newspaper headline "Boy Lands Plum Role for Top Italian Director" and suggests that the director is sexually abusing the boy. This is a reference to the sexual harassment that Robinson alleges he suffered at the hands of Zeffirelli when, at age 21, he won the role of Benvolio in Romeo and Juliet. Robinson attributed Uncle Monty's question to Marwood ("Are you a sponge or a stone?") as a direct quote from Zeffereli.
I hold the world but as the world, Gratiano,A stage where every man must play a part,And mine a sad one.(Antonio, Act 1 Scene 1)