Sarah Lancashire is no stranger to hard-hitting drama – and her latest Channel 4 venture is certainly that. She tells Gemma Dunn about it

It's been a career-defining year for Sarah Lancashire. But even with a Bafta, National Television Award and OBE under her belt, the actress - who first came to national attention 25 years ago as Corrie's bed-hopping barmaid Raquel - is predictably modest.

"I think it really depends on how you measure success," she says. "To me, a successful actor is a working actor. Accolades or recognition are purely a by-product. They're very nice to have, but I don't approach my work any differently to the way I approached it 30 years ago."

By her own theory, then, Sarah is indeed one of Britain's finest talents. In three decades, the Oldham-born star, 53, has barely taken a screen break, from her early days in Weatherfield to TV hits such as Where The Heart Is and Clocking Off. Her late forties to early fifties have marked her best years yet, having embarked on standout roles in Sally Wainwright's acclaimed dramas Last Tango In Halifax and the gripping - and much-loved - Happy Valley. Is it a sign the tide is turning for women of a certain age?

"I wouldn't read too much into it, to be honest," says the mother of three. "I think it's about the choices that you make. I don't tend to make easy choices. That's because I have to do work that I care about; I'm not terribly good at being around work I don't care about!"

For her, it's all in the writing: "It's not intentional that I choose pieces that are emotionally driven. I do like character-driven pieces; I am very attracted to those." But she confides she is never offered comedy parts, adding: "I don't believe actors should necessarily choose their own destiny."

Her latest twist of fate sees her heading up Jack Thorne's latest Channel 4 drama, Kiri. The compelling four-part serial drama examines the abduction of a young black girl, named Kiri (Felicia Mukasa), who is soon to be adopted by her white foster family, and the trail of lies, blame, guilt and notoriety that follows.

At the heart of the drama lies Miriam, an experienced, no-nonsense social worker played by Sarah, who loves and believes in her job, but has her life turned upside down by the case.

It was an offer she simply couldn't turn down. "Without a doubt, it was one of the best scripts I've read in a very long time," she says. "It just had a heartbeat. It was leaping off the page."

She lists the structure and stellar cast (names include Luther's Lucian Msamati and The Missing's Lia Williams) as big ticks, continuing: "It fills me with such joy when I hear writing of that calibre, because what keeps this piece so buoyant is the intellectual infrastructure of it. "It's so refreshing to have a piece of work that challenges you on every single level. It's so rare in your career - in my career - and a real privilege to be a part of when it happens."

While Kiri might tackle the subject of trans-racial adoption, however, Jack's writing didn't set out to give all the answers to the issues raised. Instead, it questions our responsibility, collectively as a society, suggests Sarah. "There is a sense that at the heart of every thorny political or social issue is a human being," she says, voicing her respect for "scrutinised" public sector workers. "That is what we must never forget: there is a human being or a set of human beings who deserve our love and our compassion and our security and our stability."

But she admits she won't be checking social media for the audience reaction. "I don't twit, tweet, chat. I don't Facebook, I don't spacebook, I don't do anything like that," she says.

Explaining why, she says she figured out "my life is no different to anybody else" so she doesn't do it: And as a result: "I think I've got more time on my hands." If 2017 is anything to go by, she'll need it too.

Liar writers Harry and Jack Williams have put it out there that they want to work with Sarah, for starters. "Somebody has just told me that!" she says. "What did they say: 'I'm being hunted?' It sounds a bit scary. But]it's extraordinarily flattering when you know someone, really great writers, want to work with you. It's a lovely thing to know."

But with rumours swirling that there will be another series of both Last Tango In Halifax and Happy Valley, the brothers may need to join the queue. A return to the cobbles is out of the question - "The show I was in doesn't exist any more" - but Sarah is always on the lookout for great drama.

"It's literally such a global platform now," she says of the industry. "But there's no constant. Drama will always ebb and flow, it's just a particularly brilliant period of time to be an actor, because the way we consume drama has changed. I think more than anything I'm just very privileged to be a part of my profession. I am very lucky because I love my job. I am very blessed."

Kiri starts on Channel 4 on Wednesday, January 10