Russell T Davies specifically wanted you for the role of Gwen after you played Gwyneth in "The Unquiet Dead" - is that right?
“Yeah, that's what happened. John and myself were approached about Torchwood and there were numerous meetings after that, and that's how it came about really. I was at the National Theatre and Julie Gardner and [casting director] Andy Pryor came to see my show and they wanted to meet me afterwards and it was discussed then, and I haven't quite got over that evening, to be quite honest with you, cos I can't believe it’s actually happened! It’s actually happened and we’re doing our last block at the moment. And its completely out of my control now - it’s gonna be out there ... And it’s outstanding, it’s fantastic stuff! People have asked me, ‘What's it gonna feel like when you're in London and people know who you are?’ and I just really... haven’t thought about it! I just hope that people just enjoy the series.”

What was your reaction when you saw the first script for the series?
“Aw, I just read it and it was like a film, it was like this wonderful movie script and, aw, it was extraordinary! It was like nothing I’d ever read before. And when you're reading a character that's been written for you it just instantly lifts off the page, and I just wanted to start the next day, I wanted to get into it!”

So Gwen is quite down-to-earth and she's a copper, and then she gets involved in Torchwood. How does that change her? And how does she change them?
“Well with every episode there's a different storyline, and with this underworld that she's uncovered and been chosen to join, she's changing every day. She's having to live two separate lives - it’s kind of like Clark Kent and Superman. She's got a boyfriend at home she's been with for years and years and years and then she's got a group of alien investigators who she works with, and he knows nothing about it. Y'know, he thinks I work for Special Ops - aka filing! - for South Wales Police whereas I’m chasing all sorts all over countryside, cities, towns. And she changes, she evolves throughout the entire thing. That's what's so interesting about her. It’s a new world for her and she's having to change with this new world, she's having to keep up with it. She's sometimes having to take over and sometimes she's got to ride the wave, she's riding a different wave every single day and she's learning every day, she's trying to compromise every day. So it’s constantly hard for her, but she wouldn't change it for the world, it’s what she does. "And she brings an awful lot to the team: she brings a big human thread through it, she brings a heart to it, she brings human emotion to it, she brings a police aspect to it and she brings a lot of fun to it as well. She's a very, very funny girl, Eve.”

Jack’s the hero obviously, but are there are episodes focused on Gwen as well?
“Yeah, there are. There's episodes for each character where you get to know them a bit better. You always want the audience to feel for the character or they're not gonna watch it. As a viewer you want to see yourself in someone you're watching, you wanna recognise situations, you wanna feel for these people and the people around them, when they do something wrong you wanna feel for them and when they do something right you wanna be happy for them and that's a really hard job to do. But yeah, there are some great, great episodes for Gwen: you see her struggle, her humane struggle, but also the absolutely hugeness of what she's doing and the exciting part of her life... that comes through in a lot of episodes. It’s a huge part.”

Obviously, Jack’s character’s got a lot of secrets. Is there anything secret that we don't know immediately about Gwen?
“Yeah... Yeah. I think so!”

Cagey... okay! What’s been the hardest acting challenge?
“It’s all odd having to act with the CGI. It’s incredibly hard but you've really, really got to go for it because if you don't believe in it yourself you're cheating the viewer of a good time, so you've got really indulge yourself into it - that's quite difficult.”

Doctor Who and Torchwood are all together now in this huge studio now, aren’t you?
“Yeah, it’s nuts! If you were in the 1960s and you walked up there you'd be wondering what someone had put in your tea! It’s trippy, it’s really trippy. There's witches walking about it, Shakespeare's walking about, there's goblins walking around, there's Weevils walking around, there's... things I can't talk about walking around! It’s a great place to work because it's fun, you see crazy things every day!”

So are you competitive with each other?
“There's a bit of fun banter but oh god, no! Me and John bump into David Tennant all the time and David comes on our set and we go on theirs. I mean, we scream at the crew who go over to Doctor Who from Torchwood, ‘Turncoats!’ and all that kind of stuff but it’s all done in jest. No, it’s not competitive at all. They're completely different shows and we need both of them to work for it to work as a partnership.”

Interviewer: Ian Berriman

The first two episodes of Torchwood are repeated on BBC Two on Wednesday 25 October, starting at 9.00pm.

Don't forget that SFX issue 150 (in the shops the same day) includes a five-page feature on the show!