Meet Shetland's DI Ruth Calder: Ashley Jensen reveals all

"It was mixed things — obviously I'd seen and loved the show, and I was very flattered, but it's something that has such a loyal fanbase, so there was a tiny degree of trepidation about stepping into something that is so loved. But I think what we appear to have done is that we've got the old and the new, and what's wonderful for Alison [O'Donnell, who plays Tosh] is that she's stepped up quite a lot. I think that's going to be good for the loyal fans that are a bit like, 'we want Shetland the way it was!' — it is exactly the same, but I put it as, it's just got different lights shining on it now. It's shown from a different angle, if you like."

"I think Calder arrives expecting to solve the case and not be there for very long, to be honest. She's not really there to make friends, she's there to do the job. She's incredibly professional, very focused, knows exactly what she is doing and she is very good at her job. The dynamic between them is almost between two different types of policing: urban policing from the Met in London, contrasting with a more slow-paced, sort of rural attitude, which is maybe a bit more familial than what Calder's used to. There's also a little bit of Calder that feels Tosh undermines herself a bit — Calder's a feminist and she wants women to stand up and be counted in what is predominantly a male world. So there are bits where she tells Tosh, 'you know what, you're undermining yourself by calling yourself Temporary DI', because Calder has no intention of staying there. She's like, 'you're the one in charge — embrace it!'"

"No, I hadn't, and I think that's one of the gifts of this job — you get to travel to places you never thought you would go to. There's a sort of thing where I feel like I need to go abroad to a far-flung place for my holidays, but Scotland is so beautiful. I feel really quite privileged to have been allowed to go there — and when you're working there, you see even more obscure, remote places with the locations we film in. Plus, we had a heatwave while we were there! And of course, in the costume fitting at the beginning, I'd said 'I feel the cold, I'm going to be feeble, I'll need to have warm clothes', so I'm rigged up in cashmere this, cashmere that, and then it comes to July and I'm absolutely baking!"

"When Calder arrives on the scene, it's just another murder of an informant — she's not anticipating what's going to happen. But I think she feels almost a personal bond with Ellen. She sees a bit of herself in her, this tearaway young girl that wants a bit more than just what this island has to offer at 18. So I think in some ways, that's where Calder starts to stray a little bit becasuse she lets her own personal attitudes and feelings towards Ellen kind of infiltrate the case, and it mars between her own personal situation of coming back to the island. It's not that she hates Shetland, it's having to go back and face her demons, why she left and the people and situations she kind of ran away from — which is basically what Ellen did. So there's a wee personal connection there, I think."

"Absolutely. I mean, I approached it as an entirely new job, as a six-part series that didn't have a before and doesn't have an after — for me, that was the healthiest way to do it. And having so much written into the script about the backstory for a character is immensely helpful. There's the interesting angle of the fact that people know her — it wasn't in the script, but Steven Robertson [who plays DC Sandy Wilson] and I were like, 'our characters are about the same age, we probably knew each other from school', so we ended up having that little dynamic. And she's also got ex-boyfriends, and she knows exactly who the Bain family [Ellen's relatives] are — they were a big deal when Calder lived there. So people there already have an attitude towards Calder, but she has an attitude toward everybody else!"