When I meet Phillip Breen – who is staging the Citizens Theatre’s forthcoming production of Nobel laureate Harold Pinter’s acclaimed early play The Caretaker – at the Gorbals playhouse, he is in a contemplative mood. “Pinter says he wrote the play because he was very down-at-heel and felt an affinity with the character of the vagrant. I certainly know how he feels,” he says.

Breen is referring to the eponymous character of Davies, the homeless old man who becomes caretaker to brothers Mick and Aston. Pinter, pictured right, based the drama upon a real-life situation of cohabiting brothers of his acquaintance who had, for a short time, taken in a homeless man. The playwright had spoken with the destitute man on a number of occasions, and felt his plight keenly.

“Pinter wrote The Caretaker after The Birthday Party,” Breen comments, “a play which was absolutely derided [by critics and audiences]. It closed after six performances, and was considered to be an enormous failure.

“He was living in poverty, in rented rooms, with his new wife, Vivien Merchant, and with his baby son, Daniel, at his feet. That’s what the theatre profession does to a lot of people, it infantilises them, it denigrates the traditional male role of the breadwinner, the provider and protector. This was something, coming from quite a traditional Jewish family in the east end of London, Pinter was very concerned about.”

The Caretaker is, says the director, a play “about destitution, the insecurity of one’s living space and pipe dreams of security”. Breen finds it at least as relevant in 2008 as it was when it was first staged [at the Arts Theatre, London] in 1960. The economic crisis that is currently crashing around us makes the precariousness of the characters’ lives seem extremely pertinent.

“It’s very interesting doing this play now. We're not talking about the theme in the abstract any more. Ten years ago, with Mick’s aspirations for his rundown Chiswick apartment [which he wants to turn into a flash penthouse], there would have been a sense that he was ahead of his time, and almost a sense that he’s going to be all right. Now, of course, all that stuff feels very different, it feels like pipe dreams.”

Breen believes that Pinter is “our most realistic playwright”. It’s an interesting, some would say strange, opinion. The widely held view of Pinter’s plays – particularly earlier ones such as The Caretaker and The Homecoming – is that they owe a great debt to the abstract, assiduously non-naturalistic theatre of Pinter’s great friend and mentor Samuel Beckett. Pinter’s dialogues are uncertain, ambiguous, and given to sudden, erratic shifts. Can this really be what the director means by “realistic”?

“It’s interesting to think of Pinter at the age of 29, when he wrote The Caretaker. The tradition he came from was as an actor in repertory theatre, performing in plays by people like Ibsen and Chekhov, dramas that we absolutely without question considered to be ‘naturalistic plays’.

“The characters come on and they talk to each other, they can really talk. They seem to know themselves. They’re aware of their motives, and they seem to be able to fully explain themselves. My experience with Pinter is that conversation is much more difficult than that. He sees conversation as a constant stratagem to cover nakedness. In that sense, his characters are like real human beings. They are evasive, they don't wish to be known.”

Ambiguity, the director insists, is realism. Indeed, he believes, the ambiguities and uncertainties of a play such as The Caretaker go back much further than 20th-century modernism. “I don't think Pinter’s any more ambiguous than Shakespeare, for example. One of the greatest stage characters ever committed to paper was Iago [from Shakespeare’s Othello], and we never find out what motivates him. It’s been a subject for reams of academic discourse.”

Breen – who has in recent years directed Sean O’Casey’s The Shadow of a Gunman and Brecht’s The Resistible Rise of Arturo Ui for the Citz – believes that Pinter falls on the right side of a very clear divide in theatre writing. “Good writing finds a form for something unsayable, and ordinary writing finds a form [for] something that’s eminently sayable. There are many plays in which characters seem to be able to explain themselves, and there is a lack of ambiguity. But, as a director, they're not plays that attract me so much.”

Like most people with an interest in Pinter’s theatre, the director is fascinated by how the English playwright relates to Beckett’s dramas. “There are a number of interesting crossovers between Beckett and Pinter. I think Pinter does everything that Beckett does on a philosophical level, but Pinter’s great genius as a theatre writer is that he takes it from the end of the world to the end of the pier. He takes it from the realm of the abstract and the poetical, and roots it in the popular drama of the time.”

One might argue that Beckett – who loved vaudeville and early screen comedies – achieved a similar combination of elements in his work.

However, says Breen, “Beckett’s work is on a big, more abstract political scale. Pinter’s is so ultra, ultra specific that such a thing as a pair of shoes becomes not only a power paradigm, in terms of the play, but also a fascinating political paradigm as well [a reference to the power struggle over a pair of shoes offered to Davies in The Caretaker].”

Pinter, like Beckett, enjoys playing with the theatrical context in which his work is presented. “It’s a private concern of mine,” says Breen, “to try to match plays to their environments.” The ostensibly domestic nature of Pinter’s plays has led to a trend of presenting them in studio theatres. However, says Breen, there’s something special about playing the dramas on a grand proscenium arch stage, such as in the Citz’s main auditorium.

“I love the auditorium here, I love the Citizens Theatre. It gives me great pleasure to see it come alive with plays which are written for theatres like this. It’s part of the game Pinter’s playing. He creates a uniquely theatrical experience, and to experience it in the Citz’s auditorium, with its seedy grandeur, is great.”

There’s nothing seedy, but there is plenty of grandeur in the cast Breen has secured for his production. Eugene O’Hare, who recently understudied to Kevin Spacey in Eugene O’Neill's A Moon for the Misbegotten on Broadway, will play Mick, with sometime Royal Shakespeare Company actor Robert Hastie as his mentally ill brother Aston.

Best known to Citz audiences is Tam Dean Burn, the accomplished Scottish actor who will play the title role. “Tam brings something very fresh and irreverent to the role of Davies”, observes Breen, “but he loses none of the pathos and humanity.”

If Breen’s previous Citz productions are any guide, we can expect plenty of pathos, humanity and insight from his presentation of this modern classic.