We’re here in end-of-season Southend-on-Sea to talk about Helen Mirren’s autobiography, but inevitably we spend a lot of time talking about the Queen. “I can now confess,” she says, over tea and sandwiches in a local restaurant, “that after I’d done my research and before we started shooting, I wrote to her to say we’re making this film and I am playing you and I will do my best.” And why did she do that? “Because I thought it was polite.”

Did the Queen write back? “I didn’t hear back from her directly. I got a wonderful non-committal letter from a secretary saying the Queen read your letter with interest and thank you for letting us know.” And after the film came out, Mirren says, “I was invited to dinner. I don’t think it would have just been me and the Queen, I would have been one of maybe 50. I couldn’t go. I was upset about it, but I was in South Dakota filming. I felt that [invitation] was an indication of not necessarily pleasure, but at least not displeasure.”

Do we definitely know, I ask, that she’s seen it? “No,” says Mirren. But we kind of assume she has? “We kind of assume she has. I mean, how could you resist?” She pulls apart a sandwich, discards the bread, eats the filling. Are you on Atkins? I ask. “No, I just prefer what’s in sandwiches.” She says she hasn’t eaten since yesterday, when she flew in to London from Los Angeles; it’s now mid afternoon.

When we met four years ago, I start to say, and she interrupts. “Was it that long ago? No, please! In the Savoy? I thought it was last year! What was it for?” Calendar Girls, I say. “Oh, that’s very alarming,” she says, adding archly, “you obviously made a big impression that reverberated in my memory.” I simper like a schoolgirl.

In the way it is sometimes said of such-and-such a man that he really likes women, I think you could say Dame Helen really likes men. And (I feel the generalisation is valid) we really like her. Sexy, serious, funny, bright, effortlessly flattering your vanity: what’s not to like? In any case, I’m biased: when we met before, she said I looked like an ex-boyfriend from the Seventies, George Galitzine, Prince George Galitzine no less, whose family, like the Mirrens, or Mironovs as they were then, were White Russian émigrés from the revolution. Naturally, I found the comparison rather thrilling, and was hoping for more of the same down here where the Thames meets the sea.

Still, back to the question, which was that four years ago she’d said she lived mostly in LA, what’s the situation now? “I spend a lot of time there because my husband [Taylor Hackford, film director, they married in 1997] is there. My home is England. If I was forced to choose, I’d choose England.” Since The Queen, however, and especially since her Best Actress Oscar for it, it is likely she’ll be spending more time in Hollywood. She hasn’t, she says, slept in the same bed for more than three weeks at a stretch in the past five years.

“The Oscar has iconic connotations for the Americans I hadn’t grasped,” she says. “You are, for the rest of your life, an Oscar winner. It’s like winning an honour here, it becomes part of your name. When I first came to Los Angeles, people would literally elbow me aside to get to my husband. After the success of Prime Suspect they started at least talking to me. Now they elbow my husband aside.” How is he with that? “Totally cool. He knows the way it works.”

She has just made National Treasure 2, “a full-on Hollywood adventure movie, really good fun, with Nic Cage, Jon Voight, Harvey Keitel, Ed Harris. I play Nic Cage’s mother, an expert in ancient languages.” Do you help solve whatever it is needs to be solved? “Exactly. Jon Voight plays the father. We’re estranged.” And working together effects a reconciliation? “How did you guess?” she laughs.

Would she have been offered that sort of role before the success of The Queen? “Well, ironically if I had been offered it before I probably would have turned it down. They paid me a lot more money; that’s always an incentive, isn’t it? And partly I felt, not unassailable, but I felt ‘It’s OK, you’ve done that [the Queen] and people know you can do that...’ I wanted something that was pure fun to do; something I didn’t have to angst about.” Does she have to act much in this new film? “No,” she says, and laughs. “But you have to be. A lot of people can’t act on film, they freeze up. You have to stay loose and natural.”

Would she have been sniffy about this kind of role pre-Queen? “Yes, I would have been frightened of being identified with it. You can get pigeonholed very quickly.” And now, post-Queen, you feel freed up to do more lightweight material? “Yes.” Aren’t you sort of admitting you’ve done the best work you can do? “Yeah, probably. I did feel that, not necessarily after The Queen but after Elizabeth I [a TV series she made immediately prior to The Queen]. I remember thinking you’ll never have a role like this again. I gave it everything I had.”

The young Mirren, despite instant acclaim at the National Youth Theatre and the RSC, felt awkward. “When I started acting I felt like I didn’t fit in to the Zeitgeist, if that’s the right word, of British theatrical culture. I wasn’t an English Rosey sort of person.” Also, she had had a “weird, hybrid working-class background”, and most contemporaries were posher. She can still rail against “that ‘you’re not one of us’ [attitude], that sense of privilege and, what’s the other word?” Entitlement? “Entitlement! That drives me crazy,” as do “City boys getting a f****** great bonus basically for cheating people successfully for a year.”

Her twenties were riven, she says, by self-doubt and insecurity, and neither have quite disappeared now she is 62. “I was never exuberant, I was always rather interior, rather Russian in that sense.” She was and is, she says, very much an actress who “loved imaginatively disappearing into another world” rather than a “look-at-me” type... “It’s all about continuing to work and not sitting back and saying ‘That’s it’, which I am now doing, but I don’t think I am really.”

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