How do you feel about being on the air more these days?
"The danger is always keeping the script as tight and as wholefree as possible under increasing pressure to get so many out. Our turnaround time isn't huge and I think we're doing a good job. We've got some really interesting new writers, who are all being coached under the arm of Lynda (La Plante). She's big enough and secure enough her in her own talent and brand to know that she can let these guys fly with it. So we're coming up with new stuff, which is great, and taking the characters into completely different [areas], which is great. We're shooting number six or seven at the moment."
I thought it was just five this year?
"There's five this year, but they (ITV) are also making another three to hold over for whenever suits them, I guess."
How has Connor's relationship with Walker changed over the years?
"She's a very black and white individual, very much a t-crosser and an i-dotter. She was brought on to be an antithesis to Walker. Previously he had a relationship with his DCI but with Connor it's never going to be a 'will they, won't they?' We've had great fun layering in those little touches that say they've known each other for a long time and have respect for each other. They're very combative but she respects him enormously."
For the first time, there's a story this year which you are not part of. Why is that?
"That's because in real life, I was having a baby [so] they brought in Kerry Fox. Then I came back on board."
How did you feel about your replacement?
"I never got to meet her. She's an extraordinary actress, but you're never going to feel great about it. You're being replaced! But I'm delighted I was replaced with somebody good."
In the current story, 'Conviction', we're learning about Connor's family history. What is her dad like?
"The storyline involves her dad being sick, dying of liver cancer. Connor is so uptight and driven by her job, so it allowed us to explore what would happen to this woman if her dad, who's probably the root of why she's so cold and has so many issues, was dying. I always wanted to keep a lid on [crying], because what's interesting [as a viewer] is seeing someone desperate not to cry. It was really satisfying to do, actually."
Is this the beginning of us seeing a softer side of Connor?
"Well at the moment we're shooting a relationship. She's in a relationship with a character played by Vince Regan. It's fun, quippy, light and she really opens up to him. But she screws up, needless to say, and it all goes down the toilet."
You've had some great guest stars on the show over the years. Who would be your dream guest?
"Hmm, that's a good question. In my perfect world, if I had access to anybody and everybody, I'd pick Glenn Close. She'd come in and play my mum or my sister. I think she is just somethin' else!"
Have you seen her new series Damages?
"No, I haven't been able to [watch] it so I'm going to wait for the boxset and splurge on it. I'm going to make myself sick with too much TV. I can't wait."
Often some of the storylines are quite brutal. Do you ever find it tough to film certain scenes?
"Oh, it's gruesome, it can get really tough. There was one day when they got this gorgeous five-year-old girl in and we had to ask her to hop up on the morgue slab to be pushed into a fridge. I found that really, really tough. Before every take I had to be told the worst jokes you've ever heard 'cos I just couldn't handle it. Some of these jokes were actually unprintable."
I hope you covered the little girl's ears!
"I covered my own ears!"
Is it true David Hayman (Walker) gave you your first acting job?
"He did! He was directing a TV show called A Woman's Guide To Adultery. I was at the Bristol Theatre school and basically he came in for cheap labour. He liked my hair - I had big thick curly red hair - so he put me in a scene. My first job on telly!"
You seem to be quite close to David. He's even quoted as saying he'd "go to hell and back for that lassie".
"Oh, bless him! We are as close as that. He's such a superstar and the most generous of actors and men. He sets the tone for the whole set. You can go on some sets and there could be a hierarchy but there isn't with David. Everybody gets treated with such respect. If any asshole turned up he would not tolerate it."
Finally, how long do you think the show can keep going for?
"They're questions like 'how long is a piece of string?' or 'what's going to make me money on the stock market?' Who the hell knows? We're recommisisioned every year by ITV at their leisure, so who knows? I think Trial & Retribution as a brand can go on forever. Its joy is that it has, to an extent, a formula, which gives a comfort routine for viewers. But we allow our directors total autarchy in putting their personalities on their stories. In a lot of TV you're not given that freedom any more so I think that's what gives it its air of freshness. One week it's airports and bombs then the next its small and character-driven, a completely different story. That's the joy of Trial & Retribution: any time you think you know what you're getting, they'll turn it."
Trial & Retribution airs Thursdays at 9pm on ITV1.