"It's Lindsay :) Hiya! You interested in coming to the club tonight?"

It's nearing midnight. The air outside the north London studio is still warm, and from the balcony we watch, Lindsay and I, the jagged outline of the capital twinkling in its urban peaks and troughs. Parliament cigarette in one hand, mobile phone in the other, Lindsay has decided, mid-fag break, to conduct her own mini photo shoot. 'Look! We should just do it out here,' she giggles, showing me her shots, while Rankin and a 20-strong team wait patiently inside.

Even in BlackBerry self-portraits, Lindsay Lohan is stunning. The camera does something to her. Those pretty, delicate features fall into enthralling perfection. That tiny body, childlike in real life were it not for the voluptuous chest, snaps into a fine example of womanhood. Skin and hair all in tones of faded copper. Cinema/camera/mobile phone – La Lohan was made for every screen.

She tells me that tomorrow she is making an appearance at a club night. 'You should come,' she says. She needs the company. Generally, Hollywood doesn't travel solo. If there is not a troupe, there is at least a companion, often a friend who has been segued into payroll, or an employee who has come to mean more than that. Lindsay only has Magali, a freelance PA she picked up in Paris and has known for two days, and another hired stranger, Tom, her British bodyguard, who she first met five hours ago, as he wrestled her through the waiting paparazzi scrum at St Pancras station.

She has no friends in London, she says. She looks like she has friends: the figures scuffling behind her in the newspaper pap shots, the nightclub cohorts who chat and flatter and get close. Surrounded, but alone. It's been the theme of many a starlet's life. And this one lived in a hotel for two years, maybe to ensure that someone, anyone, would always be around.

Later, she will get my number and around 24 hours from now our surreal evening together will begin to unfold. But long before that, in just a moment, actually, one of the team will come out to the balcony and try to coax Lindsay back on set. Lindsay will insist on smoking one more cigarette. Despite the fact it's midnight, nobody argues. Because merely getting her here has been an unprecedented epic of pursuit, persuasion and compromise. Now there is just unspoken relief that the shoot is happening at all.

Alarm bells start clanging when, the day before a major shoot due to start in London at 9.30am the next morning, you realise that your cover star, who was in Italy 24 hours earlier (so you discovered via a glance at Twitter), is now in Paris. With no immediate travel plans.

Naturally, you contact her publicist, to find out just what is going on. She'll sort it out. That's what publicists do.

See Lindsay's style file

But no, she can't help. The publicist says she is 'removing' herself from the shoot. Nobody has ever heard of it working like this, but from now on we must deal with Lindsay directly by text and email.

Darling, she is so sorry but she is, indeed, in Paris. She has other commitments and it's just impossible for her to make it. A day of negotiation begins. Maybe she can arrive at 12pm? Actually, more like 4pm. Twice the shoot is cancelled and then reinstated, frantic phone calls made to the dozens involved: studio, photographer, assistants, stylists, hair and make-up. After one missed train, Lindsay tweets a picture of herself on the Eurostar. This is the first time we are sure she is on her way. She arrives at 7pm, spends two hours checking into her hotel, gets to the shoot at 9.30pm – a perfect 12 hours late – and leaves at just after 2am.

There is no doubting that, once she is there, she is good. Despite the frequent cigarette breaks, despite the unyielding attachment to her BlackBerry. In the words of Rankin, 'Say what you want about the girl but she is fantastic in front of the camera.'

But there is also something entirely uncontrollable about her. Not out of control. Not 'I'll do what I want' arrogant. It's just that when you get her attention, you never know how long it will be yours. She bounces between her BlackBerry, the balcony and her iPod playlist (current favourite: Release Me by Agnes Carlsson). At one point, she's surprised by a half-eaten slice of pepperoni pizza in front of her. Between bites, she'd managed to forget she was eating it.

In the coming days, this will make fixing up a time for an interview decidedly tricky. And it doesn't seem to matter to her when she stands you up or leaves you hanging. Perhaps it is just a symptom of the child star grown up. She has been managed all her life, for a significant proportion of it by her own mother; always someone to tell her what to do, to make the arrangements, to make the excuses. There is a lot to consider when you're doing it on your own.

Yet you'd think that getting it right, right now, is more crucial than ever. Because this is all happening in the midst of a hyped comeback, with talk of renewed lucidity and professionalism. She, we, all of us, are trying desperately to shake the legacy of the past five years.

Because Lohan has form. Two drink-driving offences, two rehab stints, one cocaine find, 84 minutes in jail, 10 days of community service, numerous reports of late appearances and hacked-off colleagues. Now, it is said, she has cleaned up and grown up, willing to rebuild her career from the ground. Besides making inroads back into acting, with cameo TV roles and low-budget films, she has set up a little fashion line, 6126, which she plans to develop, and is in the midst of promoting a fake-tan range, Sevin Nyne, which she helped to create.

Yet she has the startling ability to revisit scandal again and again, like a bad-boy lover she can't give up. Take the April break-up with Samantha Ronson. Caught in an eruption of hurt and heartbreak, she vented her pain, in all its raw, accusatory, heart-wrenching detail, on her Twitter page. For all of her 98,277 (and counting) followers to read. Then she followed up with a video for the comedy website Funny Or Die, mocking her newly single status. She laid herself bare – and she did it with gusto. Actually, we liked her for it.

So perhaps the world could be forgiven for wanting to discard Lindsay Lohan. To let her sink into the tabloid abyss: the child protégée who became nothing more than a mug shot for the party-girl pack. Got wasted. Wasted her talent.

Yet despite the disappointment, the disapproval you feel at such squandering, something stops you turning away. And maybe that's it: her talent. It is easier to forgive the gifted. Tagged by Meryl Streep (alongside whom Lindsay starred in 2006's A Prairie Home Companion) as one of the brightest actresses of her generation. Commanding a salary of $7.5 million (for Just My Luck) by the time she was 20. Transforming from Disney dream teen to credible actress (by 2006, she was holding her own in ensemble drama Bobby).

Maybe our obsession with Lindsay isn't fuelled by morbid voyeurism, but by continuing hope. We watch her teetering on the edge, waiting for her to fall, hoping she will grab on. Then you meet her and you wonder – who is there for her to hold on to?

U here yet????????? Go straight to the front of the line ur on list with my name

Behind-the-scenes with Lindsay

I'm in Crystal Club, just off Oxford Street, being assaulted by commercial R&B. I was supposed to meet Lindsay at midnight. In the 20-minute lag between then and now, she has texted me twice, wanting to know where I am and that I'm OK getting in.

She is sitting in one of the sunken-sofa areas, a small rope and a large bouncer signalling she is there. Magali is to her left, Tom to her right. She is wearing a fluoro-pink vest and black shorts from Topshop, both pick-ups from a shopping trip today. (Later, she'll realise she's got the vest on inside out and will swap it for a cropped sequin number she's got in her bag.) She is, predictably, thumbs à gogo on her BlackBerry. She sees me and hugs me, seemingly genuinely pleased I've made it.

This is a different Lindsay to a day ago, when she was fidgety, distracted. She had talked about how she'd cried a lot recently and, at times, seemed close to tears again. Something was going on. At one point, she'd disappeared alone with only her journal; a black notebook in which she scribbles down all her thoughts and feelings on a daily basis. She had returned 10 minutes later, gripping it triumphantly and nodding knowingly towards Magali. I'd asked what it meant. 'She's got it out. It's done with,' shrugged Magali. Catharsis.

Tonight, there seems to be no such tension. And if any mood-moderation is required, she's certainly not seeking it through drink, the way you suspect she once did. She's currently sipping something with Red Bull. Later in the night, she will order a double Jack Daniels. That is it for the entire time I'm with her. Of course, there is another possibility for her improved mood. In this morning's press, it was reported that after leaving yesterday's shoot she'd gone on to Blake's hotel in South Kensington. And that she had stayed there until past 5am. And that she'd been with Samantha Ronson.

'We only have to be here until 1.15,' Lindsay says. 'Then we can go on somewhere else… Honestly, I can get you some leggings and a shirt from the car. It's no problem.' The zip on my backless dress has broken. I am feeling exposed. She is genuine, sweet, almost maternal.

Perhaps that's the big sister in her; being the oldest of four siblings – including her brothers Michael and Dakota and sister Ali – from a notoriously tempestuous family. She has had public battles with both her mother (or momanager, as the US press refers to her), Dina, and father, Michael, who has been jailed twice for crimes including fraud and assault. Her parents divorced in 2007 against a backdrop of allegations and restraining orders.

1.15am. The plan is to go back to her hotel. As soon as we prepare to leave, crowds gather, camera phones in the air. I had seen the paparazzi the day before, their pack mentality, their unrelenting pursuit. I'd watched as Lindsay had walked towards the arrival doors at St Pancras station and, seeing them, stopped in her tracks like an animal sensing danger. But in the midst of them their force takes me by such surprise that I am, literally, knocked over. By the time I regain my balance, Lindsay, a pro who can move in five-inch heels like nobody I've seen, is in the car. The door is closed. I am on the pavement. Lesson one of the Lohan circus: join at your own peril.

Suddenly the door flings open. 'As if I'd leave without my friend!' Lindsay is shouting. While in the car, her BlackBerry bleeps and she decides that she does not want to go to the hotel after all. She wants to go to Bungalow 8. Distracted by the paps, the driver does not hear. When we end up back at the hotel, she loses her temper. 'You weren't paying attention,' she scolds.

It's only later, when Lindsay's face is about to crumple into sobs, that the reason for our diversion to Bungalow 8 becomes clear. Sam Ronson is here. She was DJing earlier and now she is having drinks with her brother, Mark. It took only seconds for Lindsay to approach and then flee from Sam but, whatever was said, she is devastated. It does not matter that we're in the middle of a bar, that I'm a journalist who she barely knows, that Sam is still in the same room, Lindsay cannot stop the tears. She can barely speak.

She wants to go and talk to Sam. It is not a good idea. But Lindsay is not your best friend and you can't tell her that. Does she look OK? Amazing. Hair up or down? Down. This top or the other one? That one.

Soon, Sam is walking towards the exit. Lindsay tries to speak to her. Sam pauses, words are exchanged, and then she carries on. You want to stop Lindsay, beg her not to do this to herself. Sam pulls free and strides away. Lindsay is sobbing again.

Minutes later, Lindsay decides to leave. She says it will be easier if she goes alone, that she will send a car back for Magali and me and we'll meet back at her hotel.

Maybe Saturday works? Ya?

Lindsay, of course, doesn't return to her hotel suite that night. During the three hours that I wait, Lindsay chases and catches Sam. Her impromptu exit means we still haven't had a chance to work out a time for the interview. I text and she suggests Saturday.

I can see u at 7:15 to 7:30 then I have to meet with a spray tanner!

It is now Sunday evening and I am sitting in the lobby of The May Fair hotel. Lindsay didn't manage to see me yesterday. Nor, in the end, does she manage to see me for the 15 minutes she'd suggested today. Instead, I am to wait and we will try to fit the interview in before her dinner appointment. After two hours, Lindsay decides it will actually be better if we do it after dinner. She'll text me when she's done so we can meet. I know she won't, the same way you know a date isn't really going to call. Still, you hope. And just… wait, until 2am, when I finally give in and go to bed.

Sorry

It arrives at 6am. I laugh. There is nothing else to be done. In a few hours, Lindsay will fly back to LA with Samantha, the paparazzi flashbulbs that had greeted her five days earlier still there to blink her a blinding farewell.

For the next three weeks, emails go back and forth between Lindsay and her publicist – who is now back on board – and ELLE. We are prepared to do a phone interview. They are not. Eventually, just days before ELLE is due to go to print, we receive some answers to a selection of questions we had emailed over.

What do you want to achieve in the next year? I would really like to get involved in a meaningful non-profit organisation and put a lot of my energy into giving back! I have also started my own production company, Unforgettable Entertainment.

You were going to tell us about meetings you had while you were in Europe. Have they developed into anything concrete? Can you tell us more? It's top secret!

What are your main lessons of the past few years? Say 'no comment'.

The press still wants to portray you as a party girl. Is this fair? The press refuses to recognise or acknowledge the real me.

It reads like a press release. And sounds nothing like the witty, smart, couldn't-be-anything-but sincere woman we met three weeks ago. And it tells you what you knew that first time you saw the perfect image of the flawed young woman. Lindsay Lohan is a contradiction. Most of the time, Lindsay is impossible to pin down. But in the moments you are together, you will see her strip down to her soul, exposing herself so completely that you are left in no doubt as to the type and intensity of every feeling running through her.

It is when she is asked the most direct questions that she is most elusive. She cannot be constant because she is ruled by the moment. It is frustrating. It is exhausting. But it is real. And in a PR-polished world,you can no more hate her for it than you can avert your eyes from her.

Nobody can predict what Lindsay will do next. Her vows about straightening out, getting serious, coming good are made in absolute earnest. She is trying. Why can't the world see she is trying? And if, in the long-term, she is capable of steering her course away from self-destruction, then all that promise and all that talent may be enough to reshape this chapter, for the scandal to be written off as youthful folly; part of the bumpy voyage of brilliance.

But even if the script were written, there is no guarantee Lindsay would follow it. It is this uncertainty that captivates us. So you continue to watch her swaying in the breeze, weaving along the brink, and hope that, at some point, she finds a steady hand to hold on to.