To the trained cinematic eye there is a fresh and mysteriously uplifting quality about Anna Friel, Catherine McCormack and Rachel Weisz, the stars of The Land Girls. It's not easy at first, despite their obvious physical attributes and talents, to explain the sheer mesmerising power of their collective appeal. Then, suddenly, the answer takes shape with glorious Technicolor clarity: not one of them is Kate Winslet. Furthermore, closer inspection reveals that, without exception, they are also not Minnie Driver.

For these two facts alone the viewing public should be profoundly grateful. But if the young trio of British actresses recognise the extent of their achievements, they were showing no signs of it when I met up with them one wet, spring day in an empty East London photographer's studio. There were no tantrums, no histrionics, no demands. Given that every picture tells a story, I had hoped that an all-day photo-shoot might prove an opportunity to witness frame-by-frame the debauched and epic tale of three women on the edge of stardom. Instead, what unfolded was the far more familiar and mundane drama of three girls trying on different frocks. That is merely an observation, I hasten to add, not a complaint.

Indeed, I would go so far as to say that I gained much from watching this intimate, feminine ritual, not least a valuable insight into their various characters. Although by dint of once tongue-kissing a fellow actress in a soap opera, Friel is something of a household name, not much is known about her co-stars. So, in an intrepid effort to redress that lack, I can tell you that McCormack, who is model-thin yet elegantly curvaceous, is no exhibitionist when it comes to posing for a stills camera. Her two prime concerns seemed to be to conceal as much flesh as possible and to keep her large green boots on. She later explained that she was once persuaded to wear a pink bikini for a magazine shoot and happened to mention to the accompanying journalist that she attended a convent school. The net result, she claims, still embarrassed by the memory, depicted her as some kind of wanton sex bomb.

Which is not an image that one would accuse Weisz of attempting to shirk; Dark and provocatively voluptuous, the North Londoner whose name is pronounced "vice" radiates the kind of hormonal sexiness to which neither film nor photography can really do justice. As if to confirm the point, the tight, cleavage-friendly design with a split skirt that she selects leaves no doubt that she is essentially a 3-D woman.

Friel, the hyperactive sprite with a hangover, opts for a sophisticated number with straps that, as we shall see, later presents me with an intriguing professional dilemma. The look is rather sweetly undermined by the curlers she is also wearing. The message is comically astute: you can take the girl out of Rochdale, but you can't take Rochdale out of the girl.

As they outnumber me three to one, the actresses take it in turns to accompany me to a smaller room to be interviewed. It's a novel inversion of the common practice in which hacks file in one after the other, like eager johns in a brothel, to speak to the starlets. First is McCormack. In The Land Girls, a surprisingly good romantic drama set during the Second World War, she plays Stella, a strong-minded English rose who is recruited (along with Friel and Weisz) to work on a farm. I can't remember the last time I saw a woman look so beautiful on screen as McCormack does in The Land Girls. She's proud and luminous and heartbreaking.

In the flesh, stripped of the backlighting and celluloid magic, McCormack still looks a treat, in spite of her best efforts to hide it. She is uncomfortable about being interviewed and doesn't think she has anything valid to say. This has the effect of making me feel uncomfortable and causes me to wonder whether I have anything valid to ask. After deliberating on my opening question, I toy with: "Will you marry me?" But, on further reflection, I sense that it might seem a little forward.

Instead we talk about her state of mind. "I'm completely neurotic," she confesses, between dragging on a cigarette, twisting in her chair and contorting her sublime features into anxious grimaces. "I worry if I haven't got something to worry about." At the moment she must be doing a lot of worrying because she plainly has no worries.

Her progress from drama school - through low-budget film debut in Loaded to a brief, but significant, part as Mel Gibson's slain wife in Braveheart - has been as quick as it has appeared effortless.

She tells me that she's from Hampshire but that she isn't very rural. Nor is she urban. She doesn't like partying and prefers to hang out with her non-actor friends at home in Richmond. She makes herself sound wilfully suburban yet I don't think it's a fair description. She reads The Guardian and is furrowed-brow serious and genuinely nonplussed as to why anyone would court the opinions of an actress in her mid-twenties. I appreciate her point and, perhaps out of subconscious solidarity, somehow manage to mislay the tape of my interview with her - as well as with Friel and Weisz. Which means, duh, I have to re-interview them all.

When I eventually track McCormack down at home some weeks later, she's WX already finishing another film, a dark romance entitled This Year's Love. I ask what her plans are. "I'll probably be back on the old dole," she says half-jokingly, half mournfully. "I'll sit at home watching daytime TV, driving myself insane. I'll just go down the park and read and drink and make merry alone. It's not a bad life."

Back in the studio, the Verve are pumping out of the speakers and the three girls are beginning to loosen up. Weisz taunts the camera as if it were waiting on a favour. Friel, a veteran of unselfconsciousness, manically mugs away and even McCormack starts to lose her inhibitions, if not quite herself. Then Friel's mobile rings. It's Sadie Frost, another young British starlet. Friel is holding a big dinner for her friends that evening. She makes another call. "Tell Meg to book two more," she screams into the receiver. "It's a total actress table tonight." Then she hands me the phone. "Will you get it if it rings?" she asks before slipping back into frame to grab Weisz's heaving bosom. Meg is the Meg of Noel and Meg fame who, along with Friel and Kate Moss, forms a trio of friends that is Tony Blair's wet dream of hip, swinging British young talent. When Friel takes her turn to share the small room with me, she talks candidly about her friendships, neither making a big deal about the famous names who feature in her set nor pretending that hers is a normal, average life. Her self-revelation could seem an act and grow tiresome if she were a more calculating personality, but in the event it proves amusingly winning.

There's no point in interviewing Friel, it's much better just to chat. If any post-Brookside doubts still lingered about her acting ability, even after her excellent performance in Our Mutual Friend, Friel dispels them in The Land Girls. She plays Prue, a hairdresser from Manchester with an upfront approach to sex. She tells me that she was pleased with her work, but that's already history, and her thoughts race ahead to a seemingly endless list of future projects. She runs me through them before our conversation turns to the not entirely original topic of her love life.

She had a public disaster with Darren Day, who ran off with a Coronation Street starlet. Then there was an equally exposed, if less painful, fling with Robbie Williams. Now, she says, she's learnt to be more careful. "Boyfriends can come back to my flat and they can stay over and I'll even sleep in the same bed but I'm not going to have sex with them."

As I'm mulling over the psycho-sexual implications of this relationship strategy, an unfortunate occurrence takes place: Friel's left breast breaks free from its insubstantial moorings inside her flimsy dress. As a matter of both social etiquette and journalistic protocol, I wonder if I should either delicately bring her attention to the liberated tit or just ignore it in the hope that it might find its own way back. I decide, as she is in mid-flow, not to say anything.

As time passes, and the problem remains unresolved, I reconsider my stance, only to conclude that it's now too late to say anything. Still more time passes, with Friel speaking quite captivatingly about her youthful dreams and ideals and ambitions - she is "very, very ambitious" - and I am impaled on the horns of yet another dilemma. Should I vigilantly glance at the rogue breast to check that it's still out, and risk seeming a pervert, or should I continue to avoid it, as if I were entirely indifferent to its plight? Typically, when Friel eventually notices the situation she is completely unfazed. "Oh," she says, matter-of-factly, "I keep falling out of this thing."

A couple of months later, I phone Friel in Rome. She's just finished filming A Midsummer Night's Dream with Michelle Pfieffer, Sophie Marceau, Kevin Kline and Rupert Everett, and she's celebrating with a drink in a friend's hotel room. If anything, she is even more charming than before: down-to-earth without having her feet too firmly on the ground. There's a wonderfully half-formed quality about her that inspires admiration and protectiveness in equal parts. She's so determined to learn that you want to cheer, yet she's so open to the influence of others that you feel like shouting: "Watch out!"

Right now, though, the world is lying like some fantastic plaything at her feet. She tells me, after some prodding, that she's just had an uncomplicated affair with someone on set and that she is about to embark in her convertible MG, courtesy of the film company, on a holiday with a friend. After some more gentle cajoling she admits that her friend is Kate Moss. The image of these two consummate Brit-chicks driving along the Italian coast with the top down seems so unreal -like a film, perhaps by Antonioni - that I feel compelled to run through the plot again.

"Why don't you come and meet us?" she retorts. "Hop on a plane and come to Rome."

"That sounds like an interesting idea," I say (at the same time I silently run through an imaginary domestic explanation: "Look, something's come up. I have to go to Rome. More research on that damn Esquire piece").

"Are you flirting with me?" Friel asks.

"No!" I say, trying to sound affronted. "That would be grossly unprofessional."

"No, flirting's fun," she insists. "Flirting's fine even if you're in a relationship. Are you in a relationship?" "I am."

"Well, don't put it in the interview that you're flirting," Friel cautions. "She won't like that."

It's now the turn of Weisz, who has been waiting patiently, to follow me into the other room. She removes her pout from the line of the lens and walks over. The thing that I first notice about her is the stare. It's unblinking and it locks me in a grip that is, well, Weisz-like. Most people don't look at but around each other, occasionally snatching a glimpse at the face. Weisz goes eyeball to eyeball from the off. It's not intimidating nor a come-on but it is disconcerting. Which may account for why I have barely any recall of our first conversation.

We did speak a little about Ag, her role in The Land Girls. A stuffy academic, the character is, of the three, the most conspicuously cast against type. Weisz, the daughter of Jewish intellectuals, has a degree in English from Cambridge, but she is more lookish than bookish. She also made reference to Neil Morrissey, her co-star in the bad TV comedy, My Summer with Des. In retrospect it was a classic case of mentionitis, but I wouldn't recognise a "story" if it hit me in the face, which it did a couple of days later when the couple's affair was spread across the tabloids.

The fuss has long passed when she next speaks to me from a film set in the Moroccan desert. She says she couldn't believe the response. "I found it the most absurd thing." It seemed pretty absurd to me as well. I mean, what was she doing with Morrissey?

At 28, Weisz is the oldest and, arguably, the most experienced of the three. It was 14 years ago that she was selected to play Richard Gere's daughter in the sword-and-sandal flop King David. Wisely, she eventually turned the part down, following protests from her father. It was a minor role as a stroppy trustafarian in Bernardo Bertolucci's lame Stealing Beauty that displayed her gifts to a wider international audience.

On the evidence of her portrayal of Ag, though, it may be that her real strengths lie in comedy, subverting her sex-symbol appearance. She says that she is reprising some of those comic elements in the film she is making in Morocco. "It's called The Mummy. It's a big-budget adventure movie, like Indiana Jones. It's set in Egypt with an American treasure seeker and an English Egyptologist."

She's fed up with the desert and its 1400 heat. "There is nothing but dunes. A day is enough, but I'll have been here for a month when I finish." The rest of the cast are male, she says, and there is "absolutely nothing" to do but sit by the pool with 20 men each evening. Surely, I say consolingly, that must have its compensations.

"Ooh," she moans, "I'm desperate for a girlfriend. But I've become an honorary male. They've taught me how to spit and drink warm beer." She has fantasies about raw fish. "I dream of sushi. I've got cous cous coming out of my ears."

Attempting to rid my mind of that sordid image, I ask her what she is doing to amuse herself at the moment.

"I'm lying on my bed right now," she answers, "reading Seven Gothic Tales."

"Is that part of your Gothic research?"

"Funnily enough," she says, "I bought all these books on how to read hieroglyphics and stuff I haven't really studied before. It's set in the Twenties and, basically, I'm an Egyptologist who starts off with my hair in a bun and glasses in a library in Cairo and then I go out into the desert into the tombs and the hair comes down, literally tumbles to my waist, and the dress gets ripped, glasses come off and va va voom."

"What does 'va va voom' involve?"

"Only that I get taken out of my bed and end up in my nightdress. It's very fun."

Of course, it takes some creative imagination and a trained cinematic eye. But I think I see what she means.