What does the job involve?

As a writer, I think it’s easy to become overwhelmed and feel inadequate. I like to remind myself that it’s not brain surgery; it’s storytelling and it is supposed to be fun. I try to shut off the inner critic and listen to my gut.

Surely, it must be a trial sometimes?

The first draft is the hardest: it can take me weeks of procrastination; it feels like torture at times. I pace from room to room in my house, with quite a degree of self-loathing.

But there always comes a point when I hit my stride, and then I can turn out a script quickly in a day or two. Then it becomes joyful.

What is your typical writing day?

I’m quite freewheeling, but that is not something that I would recommend. I suffer from a lack of discipline and extreme procrastination. I always say, “If I’m not scared, I’m not writing.” I need hard deadlines.

Are there differences between creating your own show and working on another writer’s series?

On someone else’s show, you are a cog in the machine. That’s not a negative thing: many hands are working to create an end piece and you have to fall in line. To be good at that job, you emulate someone else’s voice. You have to appreciate that other people may not agree with you, and be humble.

When you’re creating your own show, it’s all about finding a way to punch through with your own voice.

You were an actor first?

Yes, I think mostly because I hadn’t quite realised that writing was a job.

Growing up in a council house in Wales, a profession in the media wasn’t on the cards. But I had a telly. Watching Victoria Wood and French and Saunders was the most wonderful thing – I was mesmerised by them. I wanted to do what they were doing.

However, once I moved to London and began training, I realised that writing was what I was passionate about.

Has acting helped you as a writer?

I think it has made me a better writer. I’m obsessed with writing dialogue that actors will relish. I have such a huge respect for the work they do. I use improvisation on set and I encourage the actors to contribute. If a line of dialogue is sticking in their mouths, then I’m happy to let them change it.

Do you still act?

Not often. I loved drama school but I never had what true actors such as Gabrielle Creevy (Bethan) or Jo Hartley (Trina) have in In My Skin, that extra magic ingredient. But I still perform improv comedy in London – that scratches my “show-off” itch.

How did you become a writer?

In 2012, I saw a notice for the Bafta Rocliffe New Writing competition five days before the deadline for entries. With my best friend, Matthew Barry, who’d written a couple of episodes of Casualty, I wrote a script about my grandmother.

We won the TV Comedy category, which was incredible, but, beyond that, [BBC controller of comedy commissioning] Shane Allen, who was a judge, ordered the first couple of episodes. This meant that I got paid and was able to find an agent. My entry into the industry was such a gift – but it got very difficult thereafter.

Did the show get made?

No, but no script is ever wasted. It opened a lot of doors for me.

What was the first TV show you wrote?

Sky One’s Stella, which I co-wrote with Matthew. We loved working together but, early on in my career, I struggled to get the industry to view me as an equal partner. Matthew was the more experienced of us and I had a job to convince people I could do it by myself too.

I knew I needed my own calling card, so I wrote a short film, Oh-Be-Joyful. It screened at loads of festivals around the world and won awards, and it showed that I could write by myself. Off the back of that, I got hired for Casualty.

Was that a good training ground?

Massively so. And Casualty remains the most difficult show I’ve written on. Almost every story has been told before, so you have to be really inventive – with a tiny budget and lots of other constraints.

Learning your craft on a show such as that really sets you up well for a career in this industry. It’s a baptism of fire in the best kind of way.

In My Skin draws on your experience of caring for a mother with bipolar disorder. Does this make it hard to write?

A writer needs to show unflinching honesty, which takes bravery. It is frightening at first but it gets easier, and audiences recognise authenticity.

The hardest part was juggling my responsibilities to my family, because it is not only my story to tell. I had a few months of therapy in the run-up to shooting the pilot because I was agonising over whether I should be doing it. But, while it was exposing and frightening at times, I knew that the story would help other people – and that, in telling it, I would heal myself. Writing In My Skin has been so cathartic – it is the best therapy.

What are the best and worst parts of the job?

I love writing – I can’t imagine any other job that would give me as much freedom and joy. I make my own days and I get to collaborate with amazing people.

The worst, especially for people from a working-class background, is that it’s bloody hard and very expensive to break in. I had a bursary from The Film and TV Charity to keep me going –without its help, I probably would have had to quit. By the time I became successful, I had a lot of debts to pay off.

Do you go on set?

Yes. Aside from the fact that I intensely enjoy the company of the people I’m working with on In My Skin, I also love being able to rewrite the scripts as we go. My being on set allows us the freedom to work fluidly and evolve scenes in the moment. And seeing the actors and our brilliant director, Molly Manners, work their magic is thrilling.

Are there any tricks of the trade you can share?

I’m a big fan of the “vomit draft”. I plan out an episode, and then I start writing and don’t stop until it’s finished. The key is not to re-read a scene or edit dialogue: if you hit a brick wall, just write any crap and keep going. Once you write “The end”, shut down your computer and walk away.

It’s only when you come back the following day that you allow yourself to read it and start editing. It forces you to finish a draft and, when you have the whole thing, you can sculpt it.

What advice would you give to someone wanting to write?

Watch a lot of TV and identify what you love and why. Read scripts of shows that you love and see how the writer put it on the page.

You don’t have to write autobiogra­phical scripts, but audiences want a piece of your heart. Find the courage to be vulnerable.

What attracted you to Killing Eve?

It blends genres in a way that I love. And I’m also just a huge fan of the show. Even now, one year into the job, I still get a thrill writing Villanelle’s name [Jodie Comer’s character] on a script.

What do you want to write about in future?

Issues that have affected me. I want to raise awareness about domestic violence, mental health and LGBTQ [issues]. And pierce it all with some comedy.

Kayleigh Llewellyn was interviewed by Matthew Bell. The writer is represented by Casarotto Ramsay