(bright upbeat music) - What I really like about him is that he's an ordinary man, who as a young man, went through, you know, hell in the Second World War.

Then went back to being a policeman afterwards.

And I remember that generation well.

I mean, it's my father's generation, who were frugal and modest and basically, good.

- There's right, and there's wrong.

- You know, the father son relationship can be swapped over.

There've been various moments, you know, when I could have killed someone and he's sort of stopped me and made me think about, you know, what is the difference in my moral world, between being a good policeman and being a criminal.

(laughs) - I know he's got you in his pocket.

A pony on the first of the month for turning a blind eye to hooky ham and cheese is bad enough, but this is the murder of a young girl.

(both scuffling) - He does bring a morality to it, you know?

Difficult though it is to maintain, he brings his own sense of good and bad to it.

- There's a town he's looking to.

That doesn't change just 'cause I dropped a suit size.

- I think I once said in an interview that I wanted to be in a Western, and Russell loves Westerns and he's given me my Clint moments, I have to say (chuckles), that I've loved.

- Throw the towel in now, it was all for nothing and the bastards won.

- Coughing up a bullet into a sink.

(laughing) Straightening my hat in the mirror and going out to fight the bad guys, you know.

Sometimes things can surprise you, like when Fred bought the canaries.

They've gone, I dunno what's happened to them.

Suddenly I discovered, you know, one year, that me and Win were really, really good at ballroom dancing.

Playing a character over such a long period becomes like another skin in a way, becomes very easy to put the character on.

Like very comfortable old clothes.

We're very relaxed with each other.

But, you know, he's very serious and very meticulous but also great, great fun, which I think is sort of perfect.

When he directs, he seems to move behind and in front of the camera with great ease and energy.

I'll miss him enormously, you know?

It's just great working with him.

Most films take 23 filming days, and of those 23 days we could be in Oxford, sometimes only one.

And it's a beautiful city, but it's hard to film in, especially if you're a period show.

I could hear someone running after me saying, "Sergeant Friday.

Sergeant Friday."

I stopped and she had a selfie in the end and I said, "Actually I'm a Detective Chief Inspector, and it's Thursday."

(chuckling)