What was the origin of Annika?

Nick Walker, the writer, is brilliant. I love the way his brain works. He has a very unusual take on drama. I'd worked with him before in 2010 on the Radio 4 drama Lifecoach with Stephen Tomkinson. So, when he told me he had come up with another radio drama called Annika, it was one of those moments where it was a yes before he'd even sent the script!

Tell us more about the radio series of Annika.

I love the radio series. It was set in a world of crime, which we all understand, but Annika's angle on it was very different. It took place in Norway and was very idiosyncratic. She was living in her head with a dozen different characters. You only ever heard her speaking. I've been in Annika's head for seven years now, and it's a very unusual place to live!

So, you were eager to stay on board when Nick said he was adapting the series for television?

Absolutely. As everyone knows, I've played a lot of detectives over the years. But I've been Annika a long time now, and if there was a chance of getting her fully fleshed out in a real-world environment, I wanted to be part of it. I was very keen to see how she worked transposed to life in Scotland.

What other changes did Nick make when he reworked Annika for TV?

When he started talking about a television series, my first question was, how would you populate the world which has previously only been in Annika's head. Nick said immediately, "we're going to break the fourth wall!" So, she still has Norwegian heritage, she is still an outsider, and she still has a different way of coping with life and work, but the hook is the fact that this is the only detective series where the audience is the silent sidekick. We are in cahoots with her.

Why does this device work so well?

With most characters there is so much subtext. But there is no subtext with Annika because the subtext is her talking directly to you and telling you what she feels. By the end, we are going to know her as well as she knows herself.

How did you find it filming those direct to camera segments?

On the first day, I kept stopping and laughing. It felt so wrong. But by the end, I was so into it, I was flicking looks at the camera all the time. I'm very worried about my next job now - "why does she keep looking down the lens?" It might have ruined me for the future!

How is Annika different from more run-of-the-mill detective dramas?

We are all so savvy now. During lockdown I watched more TV than any other time of my life. Nick uses all the tropes and the shape of the crime drama that we know so well, but he writes with a glint in his eye. It's the right time for something a bit naughty like Annika that will take audiences by surprise. You don't want to keep feeding people the same fare. We like a varied diet.

In what other ways does Annika differ from other TV 'tecs?

Each episode has a very theatrical murder, which seems to be at the centre of it. But really, that's not the centre of the story. What is central is Annika and her family and her team.

Annika's approach to crime solving is very unusual as well. It's very literary, isn't it?

Yes. In one episode, she uses Greek mythology to help solve a crime. She spends the whole time thinking about Agamemnon. On another occasion, she has a run-in with Michael, who tells her, "go and solve your crime with your Collected Works of Chaucer." She shouts back at him, "it's Twelfth Night this time!"

Was it hard shooting Annika during the pandemic?

Yes. It felt like the biggest leap to make it during Covid. Scotland went into lockdown while I was on the train up there from England. I thought, "can life get any more surreal?" I was terrified of the logistics of filming it during lockdown, but it very quickly became apparent that we could make it work. Nothing ventured, nothing gained.

What were the principal practical challenges?

The main challenges were the collective concerns of making sure everybody felt safe. That was done really well. There was continual testing. The pandemic also meant that we couldn't shoot certain scenes in the way we wanted, so we just had to find ways around that.

What was the hardest aspect of it?

The strangest thing was being in lockdown in Scotland without any of my family. Not seeing my family for three months was strange. It was a solitary experience on a job that is normally incredibly sociable. But the main thing was, I knew we were all safe. At the end of every day, I thought, "okay, that's another day done, and everyone is safe."

So, you're proud of making the show under those very testing conditions?

Definitely. I'm so impressed the production managed to get us all safely through a three-month shoot. When I first read the script, I thought, "this will be impossible to film during Covid." Sometimes it's only after the event that you surface and take in what you've actually done. So I was walking my dog near my house the other day and thinking, "what an achievement to have made Annika under those circumstances. How the hell did we do that?"

What do you hope that viewers will take away from Annika?

I did have nerves beforehand about doing this, but those are the jobs that you really want to do. Nick's scripts are very special. You always want to make stuff where you read it and think, "I want to be her." I hope people will think that we have taken them on a very unusual, sometimes deeply sad, sometimes incredibly funny, but always unexpected ride. I hope they feel like they are being let into a very unusual brain. Above all, I hope audiences will watch Annika and just go, "wow!"