Why do you think the first two films in this series struck such a chord?
It's a terrific ensemble every year. It's great writing, but there is also always the buzz of, "Who's in the next one?" It has a very wide appeal as well. It has what I call the "Bingo Factor". If it's discussed at the bingo by your mum and her friends, it's a success. You also know it's a hit when people from all generations stop you in the street to say, "I did like that thing you did." You just have to be sure they haven't confused you with Columbo. I have one of those faces. People ask, "Weren't you in The Rockford Files?" or, "Weren't you three steps behind Cagney and Lacey in the closing credits? Aren't you the Northern version of Harv?"
Why else have these films chimed with audiences?
You come across certain writers and you have faith in their quality control - and Jason Cook is one of those. As a writer, you have to be mindful of trying to extract too much from an idea, but Jason never does that. The most dangerous thing you can ever do as a writer is presume to know what the public who are keeping you in a job want. When you get to the stage where you think you can foist anything on them, you're in trouble. You might be running a fishmonger's and getting up at 4 am to get fresh fish for your customers. Then you start to think, "You know what? Fish fingers will do them." When you do that, you will lose custom along the way. Jason would never do that. He maintains a very high quality control, and that's what makes his scripts so brilliant.
Why have viewers warmed so much to the relationship between Terry and Gemma?
For a start, Sian is an absolutely brilliant actress - she has impeccable comic timing. Also, we get on so well off-camera, and that plays into what we do on-camera. We are playing it as straight as we can. Terry and Gemma are two normal people in ludicrous situations. We have perfected the bemused look to each other. It's great to feel that we have got that really good on-screen chemistry. It's also very nice when you can give each other notes without someone saying, "How dare you?" It's that classic thing - it's great fun coming in to work with Sian every day.
Where do we find Terry at the start of Dial M for Middlesbrough?
He's in a very good place. At the end of the first film, he got the girl of his dreams. And at the end of the second film, she's agreed to marry him. Now Terry is making all the wedding plans because he definitely needs it to happen! Gemma wouldn't have a problem with moving on - "I don't want to raise my children to sleep in the back of a bus!"
Is their relationship flagging, then?
No, but that is a danger. The hunt for the murderer is a big turn on for Gemma. She likes to see Terry step to the fore and deal with things. Gemma is happy to throw herself in danger's way.
What does Gemma see in Terry?
What women see in me in real life - a project! Terry is the emotional equivalent of an Airfix model - "I'm going to gently dismantle and rebuild you in a way that makes both of us happy." Terry and Gemma's relationship has developed slowly - I don't think Terry would stand a chance at speed dating with Gemma. They have worked together for a long time. She's looking for someone who will really look after her, and when it happens, they know each other inside out. They both have the same sense of humour.
Why does Dial M for Middlesbrough work so well at Christmas?
Because it's event television. Even though everything is multiplatform these days, at Christmas people still gather around the TV and watch things together. This is the ideal show to watch as a family at Christmas.