As David Eldridge’s new play Beginning opens at the National Theatre’s Dorfman, he talks about his son, ticket prices, inspirations and success.

We meet in his office at Birkbeck University, London, where he lectures in Creative Writing. Chatting with Eldridge about his career opens up other windows on his experience. For instance: he’s a dad (“I always think about my son Bertie when I write, and he spurs me on”) For instance: despite having written landmark plays like Under The Blue Sky, Market Boy and In Basildon, he remains very grounded. (His best mate is a fireman in Essex, where he grew up). For instance: his new play Beginning was written unsolicited, but with the National Theatre in mind (“I wrote the play and then decided the NT would be a good home for it and sent it to Rufus Norris. Luckily for me he agreed”.)

His new play explores what it means to be lonely in a big city, features two actors and has no interval. “Beginning is a real actors’ piece,” says Eldridge emphatically. “The two characters in the play are on stage for the whole evening without a break. We were looking for people who didn’t just feel absolutely right in terms of the casting but who had the technical ability, personality and guts to do it. On-and-off that casting process took seven months, much of that due to director Polly Findlay’s availability, but we wanted to be absolutely sure.”

What are the particular pressures of writing for the National Theatre? “I’m not sure that applies to Beginning because it’s the first play I’ve written in ages that wasn’t a commission for a particular management,” he says. “I think opening a play in any of the major playhouses is incredibly stressful. On the Olivier stage at the National (where Market Boy was produced in 2006) just selling the 1,150 seats for every show used to give me nightmares. I think animating the larger stages at the NT is a craft in itself and both the Olivier and the Lyttleton eat story, so you need lots of narrative red meat and actors who are on the front foot.”

I wonder how he will measure success with Beginning. “I just want to feel happy that the play has gone as well as it possibly can and that audiences have got something out of it,” he states.

“It’s nice when you can see an audience laughing and crying and reflecting upon the action of a play. But it’s also very rewarding when audiences get in touch.” He references his play The Knot of the Heart, which premiered at the Almeida in 2011. “I kid you not, every day an audience member communicated with me in person, by letter, card, email or via social media to tell me how in some way their life had been touched by addiction. It was exhausting. But beautiful and humbling,” he recalls. “Everyone wants to have nice reviews for posterity and to help encourage audiences to see the show. But I’m much less neurotic about them than I was in my twenties.”

Which fellow writers inspire him, I ask? “Robert Holman has been one of the most inspiring playwrights in my writing life,” he replies, “Robert taught me how to be a playwright in many ways; but his own work, his sense of place, theatricality and commitment to the truth of his characters is always inspiring. Caryl Churchill, as Sarah Daniels says, is “our Picasso” and she seems to reinvent the wheel with every play. Her work always pushes me to try new things and to be bold. Edward Albee inspires me to fulfil John Osborne’s aspiration to give audiences “lessons in feeling”. And I learned a lot from adapting Ibsen. I think the work I did on three of his plays helped strengthen the storytelling in my own plays.”

He reckons that the economics of theatre tickets are out of line. “Theatre going has become too expensive. There’s also a part of me that’s still the slightly chip-on-shoulder, scholarship-and-assisted-place Romford kid at the posh school; who resents how much of British theatre is still occupied by privileged white middle-class men. I think the theatre has got a bit better on that score over my writing life, but it’s still a world that can be too dominated by clever posh white people and far too preoccupied with who’s in and who’s out,” he says bluntly. “It’s why I’ve always preferred to make most of my friends outside the theatre.”

We talk about the differences in writing for television. “On screen you’re cutting away to the next scene all the time and often the cut tells the story”, he explains. “On stage you’re trying to sustain the action. Too many scene changes, inelegantly done, make for a tiresome evening in the theatre. I think TV writing, like writing for a large theatre space, eats story and you really have to pique an audience’s interest the whole time. Otherwise people just switch off and look at their smartphone or change channel.”

On the bookshelf there are various framed photographs of his little boy. How has being a dad changed his writing? “You know,” he smiles. “It’s made me more uncompromising.”

But Eldridge is acutely aware of the legacy of putting pen to paper. “I always have this gut feeling that I never want him to read or see my work when he’s older and feel his dad could have done better. I push myself. Although he doesn’t live with me, we spend a lot of time together, and that means like most writers who are parents, I organise when I write accordingly and use the time much more efficiently. There’s less procrastination when you’re a dad.”

Beginning is at the National Theatre’s Dorfman stage, London, until 14 November. Box office: 020-7452 3000.

Polly Findlay and David Eldridge will take part in NT Platform on Thursday 19 Oct, 6pm.

Now you know.