YOU are going to mention the lovely film,” she asks me right at the end of our conversation, “because I would be heartbroken if you didn’t.”

Of course when I knew that I was going to speak to Susan Hampshire I was hoping we could talk about Cliff Richard and Orson Welles, the time she appeared in a musical TV version of Dr Jekyll and Mr Hyde alongside Kirk Douglas, what it was like to have been at the heart of the 1960s youthquake, the picture you can find of her on the internet dressed in skin-tight leather and draped over the back of a motorcycle and the fact she had been a familiar face to me ever since my uncle Tommy gave us a vinyl copy of Wonderful Life not long after we got our first record player somewhere around 1973.

But, really, none of that is where her head is at these days. “Just to warn you beforehand,” she says after we’ve said hello, “if I suddenly say I have to go it’s because I’m alone in the house with my husband who’s not well and there might be a little incident. Otherwise, I’m all yours.”

Hampshire turns 80 this year, and she is a full-time carer for her husband Sir Eddie Kulukundis, the former theatre producer and philanthropist who suffers from dementia. It’s a full-time job. “It’s 24/7, yes. But I’m very happy doing it. It’s fine. I’ve had my day in the sun. It’s OK. He has been very bad but we’re turning a corner and improving, thank you very much.”

On top of that the couple are moving from their home of the last 54 years. “My only house. It’s very sad,” she says. “That’s why I’m slightly standing on the edge of a cliff. It’s normal though, isn’t it? Moves are very stressful. I need to be in a flat for my husband to make life easier.”

Mostly her typical day, she says, is about “looking after Eddie”. Getting him his breakfast, getting him up, “doing all the things that have to be done, making sure he has plenty of stimulation. I play dominoes with him or take him for a walk or, if he’s not too poorly, get him to play bridge.

“We don’t go anywhere. We are joined at the hip. But that’s OK.”

What with the caring and the imminent move – “packing up and shredding and getting rid of my life” is how she puts it – she says she is working as hard now as at the height of her working life. “Up at 6.30 and I don’t stop until I’ve got Eddie to bed.”

There is not an ounce of self-pity in any of this, by the way. “My cup is always half full as opposed to half empty which makes life much easier.” The odd episode of Casualty and Midsomer Murders apart, since the last series of Monarch of the Glen in 2005 Hampshire has effectively retired from acting. But now there is a new film. The film she is keen I talk about.

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It’s called Another Mother’s Son, a wartime true story set on Jersey of a woman hiding a Russian prisoner from the Nazis, starring an impressive Jenny Seagrove and a cast of well-kent faces (John Hannah, Amanda Abbington, Joanna David). It plays out as the kind of movie you might catch on an Easter Monday afternoon on the telly before it darkens dramatically at the end in a scene that is genuinely powerful and upsetting. And that’s not because it features Ronan Keating.

Hampshire admits she’s hardly in it. “I only get to say a few words but I’m thrilled to have done it.” The way she describes it, the whole experience sounds like a holiday. “It was just a joy to have five days away from my normal life. I don’t really work anymore because you can’t do two jobs well, can you?”

It sounds as if it’s more of a one-off than a fresh start. “If my circumstances were different I would love it but my circumstances aren’t so I will not spend one second of my life regretting or feeling negative. My life is this and I just get on with it but if another job came up and it was five days somewhere it’s lovely. But going on tour again is difficult.”

She is very stiff upper lip, isn’t she? The kind of woman who could have coped with a Nazi invasion, you imagine. As it was she spent her war accompanying her mum to Wick.

“My mother was in the WAAF. I do remember it. It was very, very windy there and I remember they had to put weights in my clothes so I wouldn’t blow off the cliff. I did go off once. I’ve still got the scar on my knee where I went stumbling.”

Hampshire was born in Kensington, her father a director of ICI and, perhaps, something of a distant father, geographically if not emotionally. Hampshire’s mother, however, kept the family and ran a small private school. She sounds a formidable specimen.

“She was a remarkable woman,” Hampshire agrees. “Although my father was there he was working in the north of England. She brought up four children and ran a school.”

As a young woman Hampshire had a 19-inch waist and was one of the last debutantes to be presented at court. Another world. “My mother, bless her darling heart, aspired because in those days you had to speak nicely and have good manners. The people who were in the echelon way above us were the people everyone aspired to. Now it’s completely different. Is it called a meritocracy now? Yes? Then it wasn’t. I was presented at court with thousands of girls. That thing has completely gone. Forever.”

Hampshire grew up struggling with dyslexia (although she wasn’t diagnosed until she was 30), which makes her chosen profession all the more of a surprise. Was it stubbornness that made her persist with a career that required the learning of lines?

“I think it was probably not being realistic at the time. And I think if you did a school concert as a child and you hear people laughing at you playing a cockney maid or something you think: ‘This is lovely. People like what I’m doing.’ As opposed to standing up in class and you can’t read.”

Of all the Susans who turned up in British films in the 1960s and 70s (and there were a few: Susan George and Susan Penhaligon, Sue Lloyd, Susannah York), Hampshire was the one casting directors turned to for well-spoken poshness and a petite turned-up nose (the result of plastic surgery). She turned up in Disney films and episodes of Danger Man before finding fame with the BBC drama The Forsyte Saga where she had the chance to play “a not very nice person. They’re always the best parts to play”.

The series was phenomenally successful. And not just in the UK. She remembers travelling to Sweden with fellow cast member Nicholas Pennell to find the streets lined with 30,000 people. “We went to a stadium where there were 70,000 people just because we were there. It was like being a mini Beatle.”

Hampshire was there when the 1960s took off. She cut a record for Decca, she had her picture taken by the photographers of the day. Clearing out the house she has found photographs taken by the likes of Terence Donovan. In short, she was very much part of that moment in British culture where everything changed.

“I was, I was. But I was a workaholic so I was not really what you would call a Swinging Sixties person,” she says. “Because I found it very hard to learn my lines my focus was totally, totally on survival. So going out partying and free love and all of that was not part of my world. I wanted to act. I got married in 1967 and I had a son and life changes anyway when you have a child, doesn’t it?”

Hampshire married French film director Pierre Granier-Deferre. Their son Christopher was born in 1971. The couple divorced in 1974. She had an affair with the actor Nicky Henson during the 1970s and then met Kulukundis at the start of the 1980s.

“We had known each other for years and years and years but not in an intimate way at all. And when he came to see a show I was in he sat in the front row. He slept probably, I think, throughout it. Never mind. He had arranged to take me out to dinner because he wanted me to present an award for something he was involved in.

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“I didn’t drink because I was driving and had a young son and was getting up early the next morning. So he had to drink this wonderful bottle of wine and he said he saw the green light and knew there and then he was going to marry me. He was very persistent.”

Kulukundis was a member of a Greek shipping family and a major figure in London’s theatreland, as well as being a financial supporter of many famous athletes, including Steve Ovett and Sally Gunnell. He was generous to a fault, his wife says.

He sounds like he was something of a force of nature, to be honest. It must have taken some adjusting to the change in his circumstances.

“The interesting thing is whatever happens in your life there’s always more good in it than bad, even if it’s not what you expect. There is a positive in everything. And I suppose … I’m not being rude about my darling husband, but he was strong-willed. And of course, let me be honest, I have control now. “He was adorable. Everybody loves him. He is totally loveable. But if he wanted X, Y and Z you went along with it, whereas now I suppose I’m in charge.”

Some of the worry has gone, too, she says. “He was very, very generous and would give money away. The telephone went all the time and he was so sweet. Ultimately he gave it all away if I’m honest with you. I don’t worry that the telephone is ringing and somebody says: ‘Can I have …?’ And he would so sweetly say: ‘Yes.’ And then he wakes up one day with nothing left. So in a way there are lots of things that are easier.”

Has this experience changed her definition of love? “I am seeing more positively the sweetness of my husband. There is so much I am enjoying about him. We are not going to have long intellectual chats or anything, but we’re having a nice Darby and Joan life whereas before we were always busy. He was always on a plane somewhere, he was surrounded by lots of people. I was very much an also-ran.”

Susan Hampshire says regret is a waste of time. There are roles she didn’t get, roles she thinks she could have played better, but she looks back on a career that lasted 50 years. “I am very lucky to have worked as much as I have and have enjoyed it on the whole. “It’s just so stupid to waste your time thinking about what you can’t have. It’s too late. Get on with it.”

Susan Hampshire is getting on with it. I tell her I will tell you she has a new film out.

Another Mother’s Son (12A) is in cinemas from Friday