Emer Kenny’s first acting job involved her simulating sex with a 35-year-old man in a ­tattoo parlour while wearing only a T-shirt, pants and a pair of cowboy boots. “I was 16, and hadn’t had much sexual experience,” says Kenny, recalling the shoot for the BBC’s 2007 Mark Haddon drama Coming Down the Mountain. “All the crew were standing watching and I was shaking with terror.” A female assistant director came to her rescue. “She noticed how nervous I was and offered to rehearse the scene herself. She made all these exaggerated whooping noises and the crew fell about laughing. Everything relaxed. I felt able to do the scene after that.”

In that moment, the teenage Kenny made a promise to herself “that if I ever got into a position of responsibility over younger actresses I’d make sure I looked after them. And now, after nearly half a lifetime in the industry, I finally have.”

Now 32 – and a familiar face to fans of the BBC’s Father Brown detective series – Kenny is the brains behind Karen Pirie, a new three-part ITV drama adapted from Val McDermid’s chilly crime novel, The Distant Echo (2003). She adapted, executive-produced and even plays a minor character in the smouldering procedural about a St Andrews police force compelled to reopen a 25-year-old investigation into the unsolved murder of a young barmaid after a true-crime podcast accuses them of not taking violence against women seriously.

“There’s nothing gratuitous in this; no needless female flesh,” says Kenny, who is determined to avoid the fetishising male gaze with which so many TV crime dramas, particularly those that feature dead female victims, are framed. “Instead, I made sure that a lot of what we witness is through the prism of the female characters. I wanted it to come from a place of real anger and deep thought.”

Much of that anger was fuelled by real events: while Kenny was writing the series last summer, Sarah Everard was killed by a serving member of the Metropolitan police. “Like so many women I felt a mix of huge sadness and fury, and it felt wrong not to imbue the show with those feelings,” she says. “I wanted to reflect the good the police do, but I also wanted to reflect the criticisms.”

The result is a terrifically tense, moody drama that pivots deftly between the present day and the original investigation. DS Karen Pirie, played by Lauren Lyle, is a breath of fresh air – a no-nonsense 20-something detective who, unlike so many of TV’s female cops, isn’t screwed up or a lonely alcoholic; just a woman in sensible trousers doing her job. Indeed, for Kenny, she is “the opposite of Gillian Anderson’s slick, sexy Stella Gibson” in the BBC 2 crime drama The Fall. “I wanted her to be someone every young girl could relate to.” They might be able to relate to Pirie for less positive reasons, too: she is only put on the case because her male superiors think it will look good to have a woman in charge. “Pirie has to prove herself in a man’s world and while I was creating the show I felt I was having to do that, too,” says Kenny. “I’ve definitely been put on writing jobs before because I was a woman. With this, I think people were surprised at how much input I wanted to have on every big ­decision. I felt Karen and I were on the same journey together.”

Kenny, who has been married to TV presenter Rick Edwards since 2016, is cheery, chatty and candid. Born and brought up in London, she comes from, as she puts it, a family of Irish builders – her grandfather, father and brother run their own business – and owes her ­interest in acting and writing to her Welsh mother, an actress-turned-drama teacher who encouraged Kenny to attend ­childhood ­acting classes. Despite landing a couple of early roles, including one in Lesbian Vampire Killers, the notorious James Corden flop commonly regarded as one of the worst films ever made – “I keep hoping it will acquire cult status but that hasn’t happened yet…” – Kenny didn’t get into drama school and turned to screenwriting instead. After being selected to join the BBC’s Writers’ Academy, at 21 she became the youngest person ever to write for EastEnders. A decade juggling acting and writing ­followed, notching up script credits on Holby City and Casualty, and appearances on EastEnders and, from 2017, Father Brown.

Yet as a young woman eager to get on, she was sometimes put in positions that she now finds questionable. In 2010, still only 20, she was painted as a naked Titania by an 80-year-old Rolf Harris for the BBC Arena documentary Rolf ­Harris Paints His Dream. “I was so keen to do a good job on that shoot, I wasn’t aware of anything darker,” she says of being asked to pose for a man later convicted of sexual offences against young women. “To be honest though, back then, as a young actress who was often expected to be pleasing, it didn’t feel any different. A lot of the jobs I was getting back then included wearing less. So to some extent, the Rolf Harris doc felt normal. Now I think... hmm, was it really necessary for me to take my clothes off for a documentary?”

Thanks to the MeToo movement – “Those women were so brave. They put their own careers at stake to speak out” – the industry is changing, but, even now, as a female showrunner in her early 30s, Kenny remains an anomaly. A 2017 study revealed that only 14 per cent of primetime TV shows were predominantly written by women. In the last five years, says Kenny, “it’s got a bit better but not much. If you’re a woman, you are still more likely to be ­commissioned to adapt something than to write an original show.”

Naturally, Kenny is determined to buck that trend: she’s already working on an original idea for a series in which she’ll also play the lead role. “It would be pretty scary,” she admits. “But I think it’s time.”

Karen Pirie starts on ITV on Sunday September 25 at 8pm