Meanwhile Kevin Whately, who plays nice guy Joe Maddison, says the characters dependable and easy-going nature suited him just fine.
I've always played the boy-next-door. I can't play flash. I can't carry it off and I don't try, he explains.
Everyman parts are the ones I seem to get. I don't know why and I'm not sure I want to know ! I've never had a matinee idol look and I've never had any sense of fashion, so I tend to be ordinary and play ordinary, which suits me.
Joe Maddison is a perfect example. He's a grafter with a strong moral sense and he's brave. I admire him a lot. There is an old-fashioned honesty and generosity about him.
Kevin was delighted to be back in his native North East for filming in the spring, which proved a family affair, with his wife Madelaine Newton also appearing in the drama as Jenny Barlow, the local gossip.
We had a flat in the middle of Newcastle while we were filming. We had two or three scenes together. We haven't acted together for a long time.
We actually met in a stage play in Newcastle. She played the lead in that and I had a little walk-on role. We also did a kids series together and she was with me in the second series of Auf Wiedersehen Pet.
To research for the role of Joe, Kevin watched several documentaries set in the 1930s, as well as reading up on the lives of World War One-platoon soldiers.
And he also drew on real-life wartime stories from his own family - his father was in the navy during the war and his uncle in the army.
My dad was on North Atlantic convoys. And my wife's dad was a merchant engineer during the war and was sunk three times and torpedoed twice. But like a lot of people who lived through it, they just didn't talk about it.
That's one of the things we try to show in Joe Maddison's War. Both Joe and Harry bottle it all up and only occasionally talk about it. It was a different time. The realities of the war were hidden from people.
Kevin had never worked with Robson Green or Trevor Fox before, but said the camaraderie amongst the almost entirely Geordie cast was absolutely fantastic.
Robson and Trevor have known each other for years and Trevor is hysterical. On screen, Robson and I could not get our punch lines in, because when Trevor set up a gag on screen he just made us howl with laughter. We completely wrecked shots because we giggled through them.
The drama also saw Kevin reunited with Melanie Hill, who he worked with in the mid-1980s on Auf Wiedersehen Pet, when she played the wife of Timothy Spalls character Barry in the first two series. She plays pretty local widow Selina.
Kevin now lives in Milton Keynes and admits filming in the North East made him feel nostalgic.
The best times are a frosty morning somewhere and you find a lovely view. The great thing is we've had fantastic locations - a lot of them places I haven't seen for 40 years. And I love being able to work outdoors.
Filming in Northumberland also brought back memories of Kevin's big break in television, playing Neville Hope in the 1980s comedy series Auf Wiedersehen Pet, following the fortunes of a group of Geordie builders as they try their hand in Germany.
The series also launched the television careers of Geordie pals Tim Healy and Jimmy Nail.
I owe everything to that show really. We were all unknown and there was a real chemistry between us. We were - and still are - like a band of brothers. Were still in touch with each other. Auf Wiedersehen Pet led directly to Morse and everything else really.
And the 59-year-old actor, who has two grown-up children and a granddaughter - three year-old Ivy - admits he doesn't try to work all the year round any more.
I like to spend time with the family. I'm a professional child-minder to Ivy three or four days a week. I love being a granddad, but I have not played one yet.