Kelly Macdonald on new BBC drama, Giri/Haji

HOW WOULD YOU DESCRIBE YOUR CHARACTER IN GIRI/HAJI?

I play Sarah, who is a detective in London. You realise in episode one when you meet her, she's sort of been ostracised in her working environment, and as the series develops you begin to understand what her backstory is.

She's a pretty broken person and her work - which had been pretty much everything - has been taken away from her.

She finds herself embroiled in this Japanese crime story and this sort of explosion of gang warfare in Tokyo; that story gets propelled into London.

COULD YOU EMPATHISE WITH HER IN ANY WAY?

I just felt like it was a good fit for me. Julian Farino [director], I've worked with before on The Child in Time, and he phoned me directly. He said, 'Can I send you a couple of scripts of the first couple of episodes?'

I was working on another BBC thing at the time; I had a bit of downtime on set because it was a courtroom scene and I wasn't on the stand yet, so I did actually have time to read them the day I got them. I couldn't wait to get my hands on more.

I think the characters have all got a common thread - they're all lonely. As the series goes on and the characters get meshed, there's this weird family dynamic, these sort of loners that end up coming together. And there's something just very sweet about it.

TELL US ABOUT YOUR EXPERIENCE ON SET...

Playing Sarah is just a joy, she’s making more of a mess than her already messy existence.

But I got to play a little bit, you know? In my experience, when you’re filming something and it feels like you’re playing, that’s when things work out the best.

WHAT MAKES THIS DIFFERENT TO OTHER SHOWS?

It's one of those dream jobs that come along. I was so lucky, my first job in this industry was on Trainspotting; I landed in this world and everybody was so excited to be there, everybody was at the top of their game and trying to achieve the same thing.

I thought every job thereafter would have that same energy, and I thought, 'What an incredible thing'. And I got to the next job and it was all very mundane, and people were there to pay their mortgages, quite rightly.

This was a very long shoot and it was pretty intense. But everybody just wanted to be there and everybody in the room is so good at what they do, so it makes me think of Trainspotting in that regard.

DO YOU DO ANYTHING IN PARTICULAR TO PREPARE FOR A HIGH-PRESSURE SCENE?

Everybody has got their little processes. But I think I'm quite long in the tooth now...

I used to get wound up, say, if it was an emotional scene. I would worry about it for weeks and then I'd have that big asterisk on my schedule, 'That's the day and it's going to be really hard', not sleep well the night before and then just be worried all day. Then you get it done and you think, 'What a release'.

Now, I trust myself more that I'm capable, and I don't have to beat myself up beforehand to achieve the same outcome.

WOULD YOU SAY THERE ARE MORE OPPORTUNITIES IN THE TV INDUSTRY NOW?

Absolutely. There's been a whole revolutionary change in TV over the past 10 years. I was lucky - Boardwalk Empire [a HBO period crime drama] seemed quite new in the way that was made.

I think there's much more possibility in TV... Films are really hard to make now. It's changed since I started my career, where it's like TV is the exciting place to be.

WHAT ROLE WOULD YOU SAY YOU GET RECOGNISED FOR THE MOST?

The one that surprises me is Harry Potter. I literally filmed my bit in that after they'd wrapped principal photography on the entire series of films, so I was brought in to do my special effects stuff and work with a cardboard cut-out of Daniel Radcliffe, because he'd already wrapped. So that I find quite funny!

IF YOU HADN'T BECOME AN ACTRESS, WHAT JOB DO YOU THINK YOU WOULD BE DOING?

I would like to have been a book editor. I was thinking about this, it's weird you asked me! I don't know why, but I think that would have been quite a good fit for me.

*Watch Giri/Haji on BBC Two and Netflix from Thursday, October 17