What's ahead in this new series?

When we were filming this series I did feel it was really strong. It's got that balance of serious and funny which our writer Mike Bullen does very well. It's getting to the stage where life is potentially more settled but also unravelling. You have to confront things which in youth people blithely ignore. It has that sense of unease and resilience which we have to bring to bear to all of our lives.

David's life takes another downward slide as he struggles to keep his dignity. It looks like an abyss for David. He's facing it but he doesn't know quite how to cope.

It's a story that acknowledges failure. And how do you measure success in life? Ultimately it's about what really matters in life. It causes a bit of reflection on that. Everybody has their own standards and values. We see people just getting by.

What's good about the downward spiral is he has people he can fall back on. What we have with Cold Feet is a disparate group. But it's actually people who are instinctively looking out for each other.

David has a strong friendship with Pete and Adam, although that can be strained. Karen and David were divorced 15 years ago and yet there is a constant connection there with different intensities for each of them at different times. Different yearnings and longings that don't always coincide.

They aren't all family but they do look out for each other. Which takes the individual characters slightly by surprise. It's just an immediate pulling together of old friends.

Is it easy in today's busy life to lose focus on things that really matter?

It's very important not to lose sight of what is important in life. I was driving on a beautiful morning today and I was starting to get wound up by the news on the radio. So I turned it off and just took in the countryside. You've got to switch off.

Mobile phones are such a distraction. In some American restaurants they come with the menus and a wooden box and you are encouraged to put your mobile phones into the box for the duration of the dinner.

For somebody who is so driven by 80s values, without being too glib a transition in his character, David does seem to come to a realignment as to what success actually means. I think David is in danger of beginning to learn from the experiences he's having. I wouldn't put it any stronger than that. But there are glimmerings of some level of humanity with David. Although I don't think we should hold up too many hopes for him. Any changes have to happen accidentally and certainly very much by degrees.

David and Karen's twin daughters Olivia and Ellie turn 18 in this series. Does the march of time in Cold Feet sometimes surprise you?

It's extraordinary how Cold Feet creates its own timeline of people's lives. It pulls people up short as to how long it's been going and, if they have watched it from the very start, how long they have been going too. People go, 'Crikey, what was I doing when that happened?' It does make people see the passage of their own timelines as well as just following what the characters are doing in the show.

In terms of David and Karen, half of David's mind is still elsewhere. He's not someone who just simply moves on. And he's still unfeasibly possessive towards Karen. Without any cause or reason at all. But it is a deep, instinctive thing he has. David has a lot of baggage.

David finds himself working in a call centre with 'motivational' quotes on the walls. Did they motivate you?

Those slogans just show you that every occupation is a performance. Sometimes if you go to the back of a shop in the storeroom you see these slogans about closing a deal and things like that. You realise every hotel receptionist, retail assistant, doctor, waiter or whoever is involved in a degree of performance. Everybody is performing in everything they do in all of their jobs. The world of work is one big theatre.

You filmed several scenes at Manchester Airport. How was that to shoot?

We obviously had permissions to film there on an ordinary working day and used a few supporting artistes. But by and large we had members of the public walking backwards and forwards in the shots going about their own business. It was done very quietly. If you don't make too much noise and don't get in the way too much then everyone at airports is so busy trying to get to their flights that they ignore you.

We also did some filming on a night bus. All of the extras were told they must not have their phones on set. So it's the only bus I've ever been on where people aren't on their mobiles.

David leads a rebellion at one stage. Have you ever done that in real life?

I've stood up for things on occasions. I don't think I've ever walked out of a job. I've only ever done acting, which is terrible really. I stand up for myself. I'm not shy of telling people if I think things are going wrong.

One episode features scenes at a music festival. Are you a festival-goer?

David has a very strange time at the music festival. But I'm not a music festival-goer myself. They had some really extraordinary circus acts on set. I'm intrigued by circus people. They are superhuman. We had a few contortionists and acrobats.

I once said about Cold Feet that Jimmy Nesbitt is the peacock lead singer. John Thomson is the drummer and keeps everything going at so many beats a second and I'm the bass player who's allowed out for a solo every now and again and then told to go and stand at the back.

What about other highlights this series?

The opening to the series pulls the rug from under the audience. You don't quite know what is going on. That's Mike Bullen playing with us again. It was a beautiful location to film in.

Mike Bullen also makes a cameo appearance in one scene involving David. Flashing his car lights. While another scene involved the closest I've got to being Jimmy Krankie.

What is the future for Cold Feet?

Life moves on and so does Cold Feet. You never know if there will be more or if this will be the end. We're reconciled to that after every series. You always have to see what the viewing figures are like. But like life, Cold Feet endlessly throws up new challenges. So there is plenty for Mike Bullen to write about.

That's the thing about Cold Feet. No-one ever knows whether it's going to work or not. We just get on and do it. But this series felt like it had both an emotional and comic weight to it. Which was encouraging. I thought, 'This is possibly quite good.'