And it is just going to have to keep waiting. Amelia Warner is one of those annoyingly perfect people. Only 18 last June, she is petite, dark-haired, intelligent and beautiful, effortlessly chic in Portobello Road grunge and Converse All Stars plimsoles. More Winona Ryder than Gwyneth Paltrow, she is about to be a huge star, but still sensible enough to defer her university place rather than cancel it. "Who knows what will happen in 10 years?" she muses, while leaning back on a BBC sofa.

Lorna Doone is the Beeb's big Christmas costume drama, full of swashbuckling, passionate romance, mud and mist. Aidan Gillen from Queer As Folk is particularly impressive as Carver, the black-clad baddie of the Doone clan, while Richard Coyle plays John Ridd, Romeo to Lorna's Juliet. This is just the first half of a double whammy for Warner. In early 2001 she appears alongside Michael Caine, Kate Winslet and Joaquin Phoenix in the controversial movie about the Marquis de Sade, Quills. When the film was premiered at the London Film Festival in November she was singled out for her spellbinding performance as Caine's teenage bride, Simone, although she was somewhat taken aback when she was interviewed just before the screening: "I hadn't seen the film myself at the time and I didn't even know if my scenes were still in it or whether they had cut me out!' She stayed in the final cut" I play a convent girl who is supposed to be grateful that this old man is marrying me But I'm taken away by him and raped" Fortunately, Sir Michael was nothing like the part he was playing: "He turned out to be amazing, funny and courteous." Which was fortunate, given the controversial nature of the film. It is strong stuff for such a young performer who had previously only had minor roles on television, but Warner is remarkably adult for her age. I have to keep pinching myself to remember that she is barely out of school.

This maturity stems largely from an unconventional childhood. An only child, Warner's mother is actress Annette Ekblom, who as Patricia Davey had an affair with Dr Shearer in Peak Practice, and is currently filming a new series. Take Me, with Robson Green. She split up with Warner's father around the time of Amelia's birth. Amelia has seen her father since,but doesn't talk about him. I wondered if Warner is his surname, but she explains that it was a grandmothers name.

Annette Ekblom was only 23 when Amelia was born and busy carving out a career of her own. Despite her Scandinavian name, Annette was born in New Brighton on Merseyside. Her daughter drops jokily into a Scouse accent stronger than anything Cilia Black has ever come out with to make the point.

In past interviews, Annette Ekblom has said that she felt guilty about farming Amelia out to friends while she was appearing on stage, but if Amelia wasn't exactly born in a trunk, the smell of the greasepaint certainly left its mark. She recalls sitting in countless dressing rooms while her mother performed in plays such as Willy Russell's Blood Brothers in the late Eighties. By the time she was a teenager she had earned a scholarship at a private school in west London, but at the age of 15 she joined the Royal Court's youth theatre. One term she and her friends devised a play and performed it in the prestigious Sloane Square venue. "I was spotted by an agent," she recalls, still surprised at the ease with which her career started.

It was only bit parts in dramas such as Kavanagh QC at first, but it soon meant she had to reassess her life. "My school was unhappy that I had a scholarship but was often away working, so I left and went to a college in Belsize Park-to study for my A-levels." She was already showing a sensible streak. While others might have spent their first pay cheques on new clothes, she continued to pick up cast-offs — albeit trendy ones from Portobello Road - and paid her college fees with her wages.

Things have really taken off in the last year. She played a schoolgirl kidnap victim in the Trevor Eve murder mystery Waking The Dead. Her character escaped: "I was the clever one,"she explains. And she was recently seen in Fifties garb in the BBC version of Take A Girl Like You. But Quills was the big break. At the time, Warner was still remarkably nonchalant: "I went up for the part, but when you are starting out you go and read for lots of parts. I thought. If I don't get this one, I'll get another." The relaxed attitude seemed to do the trick, although there was an element of aftershock when she realised how important the role was and that many of her contemporaries had auditioned too. Landing the role of Lorna Doone was more significant: "She is a really strong woman. There aren't many of those around in literature, so I was really keen."

Not surprisingly, her mother is her biggest influence. Amelia is immensely proud of what Annette achieved against tough odds. "She had me when she was very Young and then went out to have a career. It was never easy, but she worked really hard." She likes performers with integrity — Helen Mirren is another role model: "She is fantastic. I'd love to have a career like hers." She is also a huge fan of Samantha Morton, who made her name as the dysfunctional teenager in Band Of Gold and now shuttles between art-house credibility and bigger movies such as Woody Allen's Sweet And Lowdown.'' She never just plays the girlfriend."

Amelia no longer lives with her mother but, in a twist which is typically untypical, it was Annette who moved out of their Notting Hill home: "It was great. It meant I didn't have to move all of my things!" In the eight years she has lived in Wll, Amelia has seen the area change dramatically, thanks largely to Hugh Grant's bookshop in the fictional movie. "I live in the seedy bit near Ladbroke Grove, not the end where you get tourists asking (she puts on a dumb American accent), 'Can you show me the way to the door?' But I love living here. I get my clothes from market stalls and every year, a week before the big carnival, the community has a local one which is fantastic."

In a world packed with dumb, pneumatic blondes, Warner is intriguing. She is on the cusp of all sorts of things. She is in a strange limbo between normality and celebrity, childhoodand adulthood. She hangs out with her friends, goes to gigs, does what teenagers do. Yet many other friends are in their mid-twenties and her musical tastes sound like she has been raiding her mum's record collection: "The Beatles, The Kinks, The Cure... Actually, my mum was more of a Joni Mitchell fan. It's just that you hear a lot of music today, then you hear that stuff and you realise that it has already been done better." Perhaps nothing signifies this strange stage in her life better than the trip she is about to undertake when she has finished Loma Doone. "I'm going to Los Angeles this weekend for the premiere of Quills." But she also plans to visit Disneyland while she's there.

She is travelling with her Lorna Doone co-stars, Jesse Spencer from Neighbours and Rebecca Callard from Sunbum. They all became friends during the shoot, much of which was done with the Brecon Beacons doubling for the original location o fExmoor. They soon discovered that it isn't called 'Wet Wales' for nothing. "You'd be doing a scene and people would keep slipping in the mud. So before a retake you had to go off and get the mud out of your hair." No Wellingtons were allowed; period authenticity was paramount, but Warner learnt a few tricks: "I wore a corset in Quills which could be uncomfortable, so on Lorna Doone, when the corset was being done up, I didn't breathe in all the way so that it wasn't too tight."

The isolation helped the cast to forge close bonds. Between scenes she and Rebecca Callard would jump around their Portakabin, dancing to Eighties music, and light relief was provided by BigBrother. "After filming, we'd go back to the hotel to watch it. I wanted Anna to win. Richard (Coyle) wanted Craig, but because we were in a valley we couldn't get a phone signal to vote." She and Richard also had an unusual ritual: "We would thumb wrestle before every take." She shows me this variant on arm wrestling, twitching a dainty thumb: "I'd win every time.' 'The thumb looks slim and vulnerable, but is clearly tougher than it looks. Just like the rest of Amelia Warner.

BRUCE DESSAU