With the blockbuster silliness of Pirates Of The Caribbean seemingly behind her, British actress Keira Knightley bounces from the acclaim of Atonement into the equally high toned The Edge Of Love, about the romantic triangle that develops around famous poet Dylan Thomas. The Oscar nominated actress has been waiting for another great role, and this is it.

There were times on the set of The Edge Of Love when the paparazzi outnumbered the cast and crew. At times, the photographers were literally falling out of trees surrounding the film's location shoot in Wales. Their interest wasn't particularly in the fact that there was a film being made about the famous Welsh poet Dylan Thomas, but rather in the fact that playing the two ladies at the heart of the poet's tangled relationship web were Keira Knightley and Sienna Miller. It's a duo that could safely be described as a British paparazzi photographer's wet dream.

While Knightley's co-star Sienna Miller is no stranger to being hounded by paps, it could be argued that she has garnered such interest because of the high profile relationships that she's been involved in. Knightley, however, has been victimised more because of her profile as Britain's leading acting export and biggest earning movie star. As the vortex of celebrity fascination whirls faster and faster, Knightley is very much at the eye of the storm.

The actress can be forgiven when her eyes glaze over at the mere mention of this media scrutiny. It's a leading topic that crops up in every interview that she does. "You can get me ranting if you like, but it's tedious for me, and I'm sure for you," she says with a dismissive roll of her eyes. "I cannot endorse the use of harassment and stalking and intimidation, all of which are used to obtain these tabloid photographs. I understand that celebrity culture has produced a multi-million dollar media industry, but they're using illegal methods to sustain that industry, and that has to be addressed, because somebody is going to get hurt. You can't argue with that."

With the attention that the film's pap-attracting lead actresses have already earned The Edge Of Love, the inconvenience has brought some reward, with the column inches garnered for the low budget Brit flick turning into Oscar buzz. In John Maybury's WW2-era love triangle, Knightley plays Vera Phillips, the childhood sweetheart of Welsh poet Dylan Thomas (Matthew Rhys), who is now torn between her new husband (Cillian Murphy) and Thomas' volatile wife Caitlin, played by Sienna Miller in a role that Lindsay Lohan was initially slated to fill.

The film has the distinction of being written by Knightley's mother, the playwright Sharman Macdonald, who wrote the script for The Edge Of Love with her daughter in mind, though in the belief that she would play the part of Caitlin. Knightley was first given the script to read by her mother while she was working on her first film with director John Maybury, the thriller The Jacket, when she was eighteen. Her mother initially wanted her feedback. "I thought it was a very beautiful story," Knightley says. "You very rarely see films that really study friendship and rivalry, and the complexities of a group of friends and how they can implode and how they can manipulate each other. It was completely fascinating. The fact that it was based on a true event, and that Dylan Thomas happened to be one of the friends, was also very exciting. Originally when I read the script, the characters were a lot older. I was eighteen when I first read it, so I didn't even think that I could play either of the characters. But I gave the script to a producer just to try and help, and he said, 'Oh, so are you going to play one of these parts?' And I said yes, and he asked me which one, and I told him that I'd be playing Vera. It just sort of came out. I hadn't really thought about it, but I stuck with it."

Knightley is keen to add that Dylan Thomas' daughter has given the film the thumbs up. "She was very supportive, which was fantastic," says Knightley. "Even the fictitious elements of it didn't bother her. She said that her dad was a writer, so he would've approved of that! She was really great. She's actually an extra in the film."

There's no doubt that last year's consummate performance as Cecilia Tallis in Atonement, coupled with a rousing turn in The Edge Of Love, have rubber-stamped her "good actress" status. But why all the period dramas? Is it a case of doing what you do best?
"I get sent a lot of contemporary stuff," Knightley replies. "Do you know what? It's very difficult to find good female roles in contemporary pieces. I don't know why that is. I find more interesting roles for women in period pieces. I like watching period films. You can really get lost in the fantasy of them. You're not judging it on a day-to-day 'I know this reality' basis. You can completely make up your own world. I like the freedom that creates. But really, it's about the characters, and I've found that they're not as good for women in contemporary pieces."

The Edge Of Love is released on August 21.