“I’ve been making men cry,” laughs Billie Collins – writer of upcoming Corpus mainshow, Bastard – when I ask her how her latest script has been received. Collins, an established voice in the Cambridge theatre writing scene, is debuting her third play next week (following the success of Spiders and STORMFACE), a one-man show about “fatherhood, inheritance, and a talking unicorn”. We sit down over coffee to talk about the play’s conception, gestation and what Collins hopes audiences will take away from the performance.

The one-man play allows for a particular kind of audience participation

The play revolves around Charlie (Stanley Thomas), a young man who discovers that the man he’s been calling ‘Dad’ for the past twenty-one years is not, in fact, his biological father. Cue drama and a heck of a lot of introspection. Collins explains that she had the idea to write a one-man play after seeing several at the Edinburgh Fringe and becoming fascinated by their “inherent theatricality and playfulness”. Stripped of the imaginative and expressive padding of additional cast members, one-man plays pose distinctive challenges for writers, performers and directors alike. Afflicted as we are with the curse of the Millennial Attention-Span, keeping an audience engaged with what is essentially a long, long (did I mention it’s long?) monologue is a tall order indeed. It comes as no surprise, therefore, that one-man plays remain relatively uncommon in Cambridge theatre, though Jenny O’Sullivan’s excellent I’m Having a Wonderful Time in BADEN-BADEN last term is a notable and encouraging exception. Collins clearly relishes the challenge – a one-man play, she explains, “makes no pretence to realism” and so more easily draws the audience into the collective imaginative labour of the performance. Within the protean space of the theatre, the one-man play allows for a particular kind of audience participation, perfect for the exploration of the personal and the psychological.

Why fathers and sons? I ask Collins what drew her to write about this most archetypal of masculine relationships. Casting around for a character who would have a reason to speak, an “impetus to verbalise out loud”, Collins tells me that she was influenced by the great Shakespearean bastards (Edmund in King Lear will always be Best Bastard of my heart) and their love of soliloquies. Why not take the stereotypical “turn-to-camera bad guy”, and write a play about him? But Collins’ Charlie is not meant to be a bad guy. “This is not a play about toxic masculinity,” she asserts, when I ask her about the themes of the play, and what the audience discovers on its journey into Charlie’s psyche. I’m struck by how affectionately Collins talks about Charlie, as if he is someone she knows – a brother, or a friend. He’s just a young man, the kind we might all know, who’s growing up and realising that things are never as easy as you think they are going to be. Bastard is a play that draws heavily on observed experiences, which makes its promise of intimate internal exploration curiously paradoxical and equally intriguing.  It is about the things we inherit from our parents, and how we situate ourselves in relation to where we come from. Most centrally of all, it is about what we do when those points of reference fall away and we are left, ultimately, with ourselves.

Collins is full of praise for her collaborators. Director Caroline Yu is “absolutely brilliant” and it sounds like the script has blossomed under a collaborative rehearsal process. The audience, too, is welcomed into the performance to concentrate together, listen together, respond together. Music, an integral part of the production, is one of the ways in which the team hope this collective experience can be generated. Bastard promises a refreshing sensitivity to the dynamic between audience and performer, something which can sometimes feel lost in Cambridge theatre, where the audience is often assailed by the performance rather than invited into it. I ask Collins for a final summary of the play. “Funny and sad,” she says, adding after a pause, “and hopefully a little bit lovely too.”

Bastard opens on Tuesday 15 January, 7pm at the Corpus Playroom. “Now, gods, stand up for bastards!” as the Bard would say.