This could be dangerous. Last time I interviewed a white-haired septuagenarian Hollywood legend in London’s Savoy hotel he was called to heaven almost immediately. That was Richard Harris. Surely Donald Sutherland won’t die on me, too? Alarmingly, he has picked up a chill — along with rave notices — filming Pride and Prejudice in all those draughty stately homes. He keeps bidding me to move from one cavernous room to another in search of warmth. And it really isn’t that cold — for England. So when he asks one of his many female assistants to find him a hairdryer so he can blast himself with hot air, I start to worry.

Worst of all, Sutherland recalls the Harris story: that as the old roisterer was being carted off to hospital on a stretcher he looked up at a gawping gaggle of Japanese tourists in the hotel lobby and gasped: “It was the food!” Sutherland, 70, is theatrically generous about his peers. He asserts that Keira Knightley, who plays his daughter Elizabeth Bennet in the latest film version of the Jane Austen classic, can become a British Marilyn Monroe, the most “iconic” actress he has worked with — more even than Julie Christie, his playmate in Don’t Look Now, with that most energetic of cinematic sex scenes.

The fairer sex is a species that thrice-married Sutherland knows intimately: he has flown in from Venice where he watched a restored version of his wonderful Casanova, for which the director Federico Fellini insisted he must cast Sutherland, “a sperm-filled waxwork with the eyes of a masturbator”. Yikes, no wonder Donald enjoyed our Keira in her corset.

Actually, Sutherland looks elegantly, elongatedly languid in a deep green suit and loosened blue tie, still with a lustrous mane. Not that his gentlemanly demeanour stifles some salty opinions, even about his old lover and fellow peace campaigner Jane Fonda for launching an anti-Iraq war-bus tour of America. Oh, and more surprisingly still, the Canadian-born star, who has enjoyed a renaissance with recent hits such as Cold Mountain with Nicole Kidman, says he is broke thanks to the pernicious British taxman.

We start with Pride and Prejudice, which he nearly turned down declaring himself “too old, too busy and too Canadian”. Why the conversion? “I’m always too tired,” he sighs in that hypnotic baritone, almost a lion’s growl. “But my age was right. Mrs Bennet is forever telling her husband that he is going to die at any moment.”

Sutherland has learning where many actors merely have vanity. He talks about how in 1811, when the story is set, women had it worse than any before or since. Families like the Bennets with five girls and no heir were right to be desperate: unmarried daughters faced ruin. “Morals were strict, and the hopes of women rested on the men who would take them.”

But is preening in a petticoat at all relevant today? “My God, it is,” he booms. “Particularly in the United States where they talk about family values but leave people to drown.” Sutherland enjoys rhetorical flourishes, and soon he is off: “In France they might not earn as much (as in America) but they work a 35-hour week and they spend time with their families; isn’t that real family values?” Soon we have covered 9/11, touched on the “evil” that is Tony Blair and been through a rant about the war in Iraq and why it is a bigger crime than Vietnam.

Despite his vehemence, Sutherland will not hitch a ride on Fonda’s anti-war bus. He, of course, was her partner — political and pillow — on her famous tour against Vietnam: “I don’t think that serves a lot of purpose. It just gives Karl Rove (the president’s chief fixer) the excuse to divert attention; it gives them a point of attack. And I don’t think that is a good idea.”

Because they will dredge up pictures of “Hanoi Jane” seemingly admiring enemy guns? “They can do what they want. They lie. This is one of the most mendacious governments in the history of the world.” This is a reference to the last presidential election when photos were doctored to give the impression that John Kerry, the Democrat candidate, had shared a platform with Fonda. “I was there and I don’t even remember Kerry’s presence.”

He sounds, I tell him, even more passionate about politics than about Pride and Prejudice. He snorts: “The only thing I feel passionate about is my wife. But no, I love acting, it’s a wonderful job. Joe Wright (the young director of Pride and Prejudice) has given it time, which is rare now: he allows the audience to enjoy the emotions, the countryside, and is so loyal to Austen. People talk about Olivier in the 1940 film and Colin Firth in the BBC adaptation, but Austen was writing about women, and this film is about women: the fear of not having an inheritance, it is like that line from Six Degrees of Separation — it was hand to mouth at a higher level.”

Wright said he was petrified telling Sutherland, a star for half a century, that he was overacting. Did Sutherland mind being bossed around by this “upstart”? He insists not, adding: “In these very rooms I nearly said, ‘Look guys, get me out of this film. I’m going to disappoint you terribly’.” Sutherland is a superb, possibly great, actor; but probably a rather exhausting workmate.

We move on to Knightley and at first you think he can’t be serious, but Sutherland is always in earnest, even when joking. “What a joy that girl is,” he says. “Terrific. I watched her on the set and she listened, she heard, she was compliant. But more than that she brought out of herself truths about the character.”

With all his lovely leading ladies, who was the most iconic? “Keira Knightley.” I laugh: more than Christie or Fonda? “Absolutely. You said iconic. She reminds me of Marilyn Monroe, but with more humility. She is a very simple artist. She is — or appears to be — without vanity or artifice.” He puts on his Mr Bennet smile: “I have had a lot of wonderful daughters.”