Film preview: Harry Potter and the Deathly Hallows: Part 2

"WITH Harry to the End", declared one home-made sign in Trafalgar Square yesterday, where thousands of fans had begun camping as many as three days before tonight's world premiere of the final film in the Harry Potter saga.

They had gathered for the chance of catching the stars of Harry Potter and the Deathly Hallows: Part 2, in a red-carpet event in one of London's most famous locations, ahead of screenings at three cinemas in nearby Leicester Square.

The film opens across the UK next weekend - a decade after the first movie in the series screened. Early reviews emerging yesterday - ahead of an official embargo until tomorrow - ranged from good to glowing. Director David Yates called his finale "like a big opera with huge battles". Surprisingly, several critics suggested that, if anything, the film was better than author Joanne Kathleen Rowling's wordy original, the last of seven books.

In June 1997, JK Rowling's schoolboy wizard Harry Potter emerged as the boy who led a whole generation of children back to the pleasure of reading. Harry Potter and the Deathly Hallows: Part 2 - the final confrontation between Harry and his nemesis, Lord Voldemort - closes off what has become a 4 billion film franchise.

The finale of Harry Potter - without giving too much of the plot away - could conceivably leave scope for a "son of Harry" spin-off in some distant future. But with Rowling ruling out another Potter book, today may be the day when her millions of fans, and the film series' most famous names, have some growing up to do.

When Rowling sold the film rights to her novels, she insisted home-grown actors should be cast and that the movies should be shot in Britain.

The result was to turn child prodigies Daniel Radcliffe, then 11, Emma Watson, nine, and Rupert Grint, also 11 - Harry, Hermione Granger and Ron Weasley - into global stars, while showcasing British talent from Robbie Coltrane, playing the gentle giant Hagrid, to Helena Bonham Carter, as the witch Bellatrix Lestrange, and Michael Gambon as Albus Dumbledore.

Now 21, Radcliffe has worked beyond Potter ranging from a 2007 outing in the play Equus to his latest stage role as J Pierrepont Finch in a Broadway revival of the 1961 comedy musical, How to Succeed in Business without Really Trying. He plays a bow-tied window-cleaner on the make in Manhattan. With reviewers inevitably turning their pens on any Potter star, his performance was judged "capable" rather than captivating. Recently, Radcliffe revealed how he had become teetotal after developing a dangerous "reliance" on alcohol. "There were a few years there when I was just so enamoured with the idea of living some sort of famous person's lifestyle that really isn't suited to me," he said.

Watson, seen as the most promising prospect after establishing herself as the series' winsome know-it-all, escaped to the US two years ago to study English at the prestigious Brown University. Early this year, however, the seemingly level-headed daughter of a communications lawyer put her courses on hold to focus on modelling and acting. The 21-year-old is due to appear as the love interest in the film of The Perks of Being a Wallflower, a story of adolescent angst and sexuality written and directed by Stephen Chbosky.

While she is pursuing other film roles, Watson said recently that she may try to steer clear of the Hollywood scene. "Los Angeles scares the c**p out of me" because of its obsession with looks and weight, she said. "I feel if I have to work out four hours a day, and count the calories of everything I put in my mouth, and have Botox at 22, and obsess about how I look the whole time, I will go mad. I will absolutely lose it."

Grint's planned next film role is as British sports eccentric, the Olympic ski-jumper "Eddie the Eagle" Edwards. Grint, now 22, has found the end of the Potter films emotional but "liberating". He is also said to be considering a lead role in Wartime Wanderers, a wartime football film.

Among actors who came to the film with fully-fledged careers, Ralph Fiennes has excelled in the role of Lord Voldemort, while Alan Rickman has won praise as being "delightfully sinister" in the role of Professor Severus Snape, the arch-villain on the staff at Hogwarts School. Bonham Carter took the "tiny part" of witch Bellatrix Lestrange in Harry Potter and the Order of the Phoenix after Rowling reportedly told her that the role would get more significant in later instalments. She perfectly filled the part of the series' most malicious female character.

Even for actors in lesser roles the films have been life-changing.

Bonnie Wright, who first appeared at the age of nine, is now 20 and again takes the part of Ginny Weasley, Harry's girlfriend. She is engaged to fellow Harry Potter actor Jamie Campbell Bower, playing wizard Gellert Grindelwald. Irish actress Evanna Lynch, 19, took the role of loopy Hogwarts student Luna Lovegood as her first experience of acting. "You'll make more films with new crews but you see the people on Harry Potter all the time so it's like a family," she said, as she pursues her own acting career. The future of Rowling's writing remains the best-kept secret of all. This month, in a sea-change in the management of her literary life, she split with agent Christopher Little. He found the publisher for her first novel Harry Potter and the Philosopher's Stone in 1996, after a series of rejections, and remained at her side as her books went on to sell more than 400 million copies.

The reason for the split, which Rowling called a "painful decision… not taken without good reason" remains unclear, but it may be tied to the surprise launch of the Pottermore website in October. Rowling, whose wealth was estimated at more than 530m in the latest Sunday Times Rich List, will use Pottermore to issue previously unpublished material and to sell digital and audio books directly to readers, by-passing the middlemen. "It is true to say that finishing writing Harry, I have only cried that much, ever in my life, when my mum died," she has said. "I've never cried for a man like I've cried for Harry Potter."

In Scotland, the Cineworld chain marks the premiere week by screening all the Harry Potter films from tomorrow. In Trafalgar Square last night, as storm clouds threatened a rainy premiere tonight, 8,000 wristbands were handed out allowing queuing fans to escape the downpour and return to the viewing pens - but many vowed to stay put. Guests for the screenings were to be transported between the squares through a mock-up of the magical Diagon Alley featured in the films.

Mar Gallarado, 20, and her four friends from Spain had rushed from Gatwick Airport to Trafalgar Square with bags in tow after flying in from Barcelona to ensure she got a good place in the crowd. She said: "We are Harry Potter freaks, I guess. We will camp out overnight and try to claim a spot near the front. This is the first premiere we have ever been to and it is the last Potter film. We can tell our grandchildren about this." She has read the books in Catalan and Spanish, but only recently in English.

Stephanie Desmaris, 25, and her 24-year-old friend Jesabelle Lefevre saw the first film together as teenagers in Brussels. Stephanie said: "My father was in publishing and gave me the first Harry Potter book and said this is really big in Britain. I was 14 at the time. I read it and was hooked. I'm 24 now and still a fan."

American fan Chloe Bitter, 20, flew in from Utah. "It is Harry Potter. We are a little obsessed by it all, but this is something that has been part of all our lives," she said. "We grew up with the books and the film. I think the first book was the first book I ever read."