Helen McCrory interview: Diamonds and David Bailey, darling! We spent [this] Christmas in Wales. It was just rain and muddy water, but the kids are so good now that they'll march for two and a half hours through it. McCrory realises how this sounds, laughs, then corrects herself. But you know, it's not mad, driving gales. It's just mild winter drizzle. We're not one of those families who say to their children [and here she affects a gruff military voice]: 'It's character-building. Let's send them to boarding school at the age of four. No, no, no, none of that crap. Her children, who are four and five, have kindly decorated her diary with glittery paint "and my iPad. And Damian's, too. At least nobody will nick them. She eats pesto soup and drinks tea. We talk about her dislike of Kindles, swap book recommendations, and discuss the films The Iron Lady and The Artist, as well as Charles Dickens. McCrory is difficult to interview not because she has nothing to say or is unfriendly: on the contrary, the opposite is true. But it means that you can end up talking for a long time about nothing at all, as if you were old girlfriends, before you catch yourself and try to remember why on earth it is you are here. What are we supposed to be talking about again? We'll Take Manhattan, the BBC drama that chronicles the Sixties romance between David Bailey and Jean Shrimpton during their first Vogue shoot in New York. McCrory plays Lady Clare Rendlesham, the magazine's then editor, a formidable woman who was a sort of early-prototype Anna Wintour. The actress steals the show from Karen Gillan and Aneurin Bernard, who play the lovestruck couple, as she strops around Manhattan and weeps fabulously through false eyelashes so long that she could probably take off into flight wearing them. The day we meet, McCrory has yet to see the programme, but is off to a screening hosted by Bailey himself. She has never met the legendary photographer before and tells me that she is "absolutely terrified." In the film, Lady Clare comes across as stuffy and backward-looking, whereas in reality she was quite revolutionary in fashion circles. "She championed clothes that were chic and wearable," says McCrory of her character. She pushed [Mary] Quant. She had four children, and in those days it was difficult to be a mother and hold such a powerful position. I think she was, by all accounts, terrifying to work for, because she knew exactly what she wanted. That certainly comes across in the film, but McCrory says that "you're not really playing the person. You're playing the writer's idea of them. It was the same with Cherie. Cherie, as in Blair, is a character McCrory has played twice, in The Queen and the follow-up to that film, The Special Relationship. She met the wife of the former prime minister back in 2003, when Cherie came to see a production McCrory was performing in at the Almeida Theatre (McCrory is something of a veteran at treading the boards - she helped to set up the Landor Theatre in South London, has performed at the National and the Donmar, and has been nominated for an Olivier). I went to the bar afterwards and there was just a little corner table, and there she was with a sort of security man standing next to her. I chatted to her for two or three minutes, and she was completely different to how she had been portrayed in certain papers. I mean, she was really funny, and pretty. She must see my face contort in surprise. Yeah, she was quick to laugh. Light. And attractive. I felt quite defensive of her after that. Has she been in touch with Cherie since? No, but I did read an interview with her where she was asked who she'd like to play her in a film of her life. And she very kindly said: 'Oh, Helen McCrory seems to be doing a good job. That was very generous of her. I can't imagine her ever playing Sam Cam. With respect to the Prime Minister's wife, she's too quiet, too comfortable in the background, and McCrory seems to revel in strong characters - Lady Clare, Cherie, Narcissa Malfoy in the Harry Potter films. I've met her a few times [Samantha Cameron] and she's a very nice woman, but I'd have to wear very, very high heels. She's tall, isn't she? McCrory is currently filming the new Bond movie, Skyfall, the set of which was visited the day before our interview by David Cameron. "He came with Julian Fellowes," says McCrory, looking a little puzzled. I think they might be on some sort of film committee. I didn't get to meet him as I was having my make-up done and by the time I came out he was gone. Sadly, McCrory cannot reveal anything about her character in Skyfall, or any details about the plot. But, after years of theatre, she is suddenly excited about the medium of film. I used to say that theatre was my favourite thing. But the more I do film, the more I appreciate it. It's my new crack. She lets out a wicked cackle. No, she adds, she has never done crack. Dirty drug. After the interview and pictures, the photographer offers to give McCrory a lift home with all those diamonds. The actress apologetically accepts, a little embarrassed. And off she goes to prepare for her trip to Hollywood. Like everyone says: normal, in a glamorous sort of way. We'll Take Manhattan will be broadcast on Thursday, January 26, at 9pm on BBC Four