Christopher Timothy is walking on the beach in Blackpool when we speak, shouting to be heard over the strong winds.

Unable to meet in person due to his touring schedule, this is as good as it’s going to get. And it’s reassuring the 71-year-old is choosing to blow away the cobwebs between shows, rather than stay in his hotel room.

But he’s the first to admit his age has not dented his enthusiasm for his profession, or his zest for life, and he’s as busy as ever. “I’ve been working pretty constantly for the past five years and I’m happy,” he shouts, agreeing to find shelter so we can at least talk rather than yell at each other, before adding: “And I do love what I do and know how lucky I am, because job satisfaction is a rare reality these days. So I count my blessings.”

Currently starring in The Diary Of Anne Frank as Otto, Anne’s father, opening at The Playhouse from Tuesday, I wonder if he feels great responsibility along with the role? “I know I should feel one and deep down I probably do, but when I play the part I’m thinking about Otto as a father and a husband fighting for his family’s life,” Christopher says.

And then he goes further: “So I read The Hidden Life of Otto Frank and worried about what was and wasn’t in the play before realising ‘this is a play of the diary, just play it’. So I have done my research and tried to find out as much about Otto as possible, because he had flaws. He wasn’t a saint, he was a human being, but he was a good man.

“And I know Otto edited a lot of Anne’s diary out, so the bit about her sexual awakening is non-graphic.

“But I’ve got daughters and although they talk to their mother about that sort of thing, I’m not stupid. So I find this piece beautiful.”

And then he smirks: “But the audience is quite young, they do tend to giggle during the sex speech. To start with I thought ‘Oh do shut up,” and then I’d remember what it was like and say ‘come on now’ to myself.”

Having seven children himself, Christopher Timothy is well aware of teenagers’ peccadillos and the angst they all go through. “That’s the strange thing about this play: it’s all seen through the eyes of a 13-year-old girl. And I wonder if 20 years later she’d think twice about what she wrote, had she survived.

“But it’s delightful to have a young audience, because when you have their attention you can cut the silence with a knife.

“And that’s the point isn’t it — to get young people into the theatres?

“So I’m delighted to have done this and I’m enjoying it — it’s very different from anything I’ve done before.”

You mean it doesn’t have a doctor or a vet in it? Christopher roars with laughter. Because we can’t get through an entire interview without mentioning his parts in All Creatures Great And Small, James Herriot’s fantastically successful TV series which made him a household name, or his TV soap role in Doctors. And yet ACGAS nearly didn’t happen, the casting directors wanting his part to go to ‘a name’.

“Yes, I was lucky, maybe it was a whim. But the fame was pretty instant, with people coming up and asking for my autograph and I remember thinking ‘wow this is it’.”

And now? “Now I circumnavigate away from those situations. And on the whole people are fairly polite, although they still stand next to you in lifts and have that conversation: ‘It is, no it isn’t, yes it is’ and if I’m in a jolly mood I’ll say ‘yes it is’. I don’t know how strong a pull I am now, but I’m the only one on the poster, so if that gets bums on seats, good,” he grins.

His grand-daughter is studying music in Oxford, so Christopher hopes to “hang out with her between performances without all the usual clutter of the rest of the family.”

But he loves it when they all (seven children and three grandchildren by his two wives) get together. “Everyone has their own lives and their own circle of friends don’t they?

“But I do like it when we all manage to meet up. I love watching them all, arguing away and now I’m old enough for them to be able to say what they want to me.”

The question is though, is Christopher feeling youthful enough to go on Blackpool’s roller-coasters?

“God no! Not because of my age but because they scare the hell out of me. Why would you want to do that?” he protests before heading out into the blustering winds and I have to strain to hear his final words.

“But my enthusiam for life has never dimmed, if anything it’s better now. So I never want to stop learning.”

The Diary Of Anne Frank is at Oxford Playhouse from May 22 to 26. For tickets, call 01865 305305 or visit www.oxfordplayhouse.com