It's Valentine's Day, 1968. In a hospital in the south London neighbourhood of Wimbledon, a daughter is born to Lord and Lady Henshingly-Croft. The girl has a drawerful of silver spoons in her mouth. Between the ages of three and 11, she is privately tutored at home; she then attends Wimbledon High School for Girls and Gordonstoun.
At the latter, she discovers a passion for rock climbing in the mountains of Scotland. (She also takes up shooting, but is soon banned for showing "too keen an interest".) By the time she is 18, everyone can see she has a wild streak, but her parents believe she can be thoroughly civilised - and eventually married off to the Earl of Farringdon - after three years at a Swiss finishing school.
While in Switzerland, however, the young woman takes to extreme skiing and spends a holiday pursuing the sport in the Himalayas.
On the return journey, her plane crashes deep in the mountains, and she is the only passenger left alive. Somehow she survives and, two weeks later, staggers into a mountain village. By this time, the course of her life has changed. She feels truly alive only when travelling alone. Lara Croft has decided to become an adventurer.
Or you could look at it this way: Lara Croft was born on the screen of a computer in an English video-game studio in 1995. First, she was a pencil sketch on paper, then a series of more detailed illustrations. Next, her vital statistics were plotted on a VDU screen. Thousands of triangles meshed together to build a computerised outline of a female form.
At this stage, Lara would have looked like a sculpture in chicken wire. Then the figure was "skinned" - wrapped in shaded, coloured surfaces to approximate a clothed human being. Lastly, she was animated: taught to walk, somersault, run and pull herself up on rocky ledges. Virtual worlds were also built around her to test her physical abilities to the limit.
Lara Croft and the Tomb Raider franchise are the products of Core Design - the game-development studio where Lara was born - and Eidos Interactive, its British parent. The man who fathered her was an artist in his early 20s called Toby Gard.
"When I came up with the idea for Tomb Raider," he says, "it wasn't necessarily going to be a female character. We wanted a real-time cinematic game, and I designed a couple of characters; one was a girl, one was a bloke. Eventually, we realised there was going to be a lot of story element in the game and we couldn't keep both the characters, so it was back down to one." So which should they choose? At the time, a female lead in a game was almost unheard of, Gard says. "There was resistance from marketing quarters, saying that female characters never sold."
Eventually, Core chose Lara as a refreshing antidote to the muscled meatheads that usually populated video games. And boy, did she sell: 26 million units, and counting, earning about $1 billion gross in retail sales.
Having turned her back on the upper-class society of her parents, who terminated her monthly allowance in disgust, Lara metamorphosed into a modern-day Indiana Jones.
For her first commission as a professional tomb raider, she was hired to retrieve the three parts of a mysterious artefact known as the Atlantean Scion. Hurtling through Peru, Rome and the lost city of Atlantis (well, it wasn't lost any more), Lara negotiated booby traps and shot a variety of wildlife, including rats, tigers and, alarmingly, a tyrannosaur.
In later quests, she travelled to Venice, Tibet and the Great Wall of China, snuck around the US military institute Area 51 and battled goons in the London Underground. Along the way, Lara was constantly learning. On the trail of a weird dagger that could turn you into a dragon, Lara discovered that she could climb walls, flip through 180 degrees while jumping or swimming, and wade into shallow pools of water.
By the time of her next adventure she could even get down on her hands and knees - in order to negotiate low tunnels and ventilation ducts - as well as monkey-swing from walkways and run much faster than she ever had. She could even blink. The programmers at Core extended Lara's capabilities with each new game, exploiting the fact that she had become a star.
Every year, another sequel popped up just before Christmas and went straight to the top of the video-game charts. Meanwhile, Eidos, Lara's parent company, was becoming a stock-market darling. In 1998, the World Economic Forum in Davos, Switzerland, named the British firm the world's fastest-growing company, and in the summer of 1999 Eidos's share price was trading at a delirious high of $18.20.
Lara Croft, we must note, has brains as well as beauty. She is said by her biographers to have penned several travel books, including A Tyrannosaurus Is Jawing At My Head and the follow-up, Slaying Bigfoot. But she clearly does not read the newspapers or watch television, for in none of her adventures do we see any awareness on Lara's part that she has become an international media darling.
The first wave of Lara coverage came shortly after the game's 1996 release, with David James, the Liverpool goalkeeper, explaining to the London Times that he was playing badly because he had been staying up late playing Tomb Raider. In 1997, U2 used specially commissioned digital footage of Lara in action on their Popmart tour.
Lara appeared in comics, and plastic action figures of Lara sold like hot cakes. The original game had appeared on both the Sega Saturn and Sony PlayStation consoles, but Sony soon signed an exclusivity deal that meant episodes two and three would appear only on PlayStation.
Then came the acme of media acceptance: Lara on the cover of the Face in June 1997. Not only was this the first time the style magazine had used a digital person on its cover, it was the first time it had allowed an image to interrupt its red masthead. Newsweek, Rolling Stone and Time soon followed suit, and a video for the German pop outfit Die Artze, featuring Lara fighting with members of the band, went heavy-rotation on MTV.
Marks & Spencer produced a range of Tomb Raider III merchandise. Douglas Coupland, the writer of Generation X, contributed to a fey devotional tome entitled Lara's Book. In November, 1998, Tomb Raider and its first sequel were awarded Millennium Product status by the British Design Council.
In 1999, Lara - or rather Core Design, won a BAFTA for her "outstanding contribution to the interactive industry". In 2000, filming began in England on the imminent Tomb Raider feature film, budgeted at $100 million and starring Angelina Jolie. You can now, if you wish, clothe your children in nattily miniature Tomb Raider threads.
Perhaps the cleverest marketing coup was the association, begun in 1999, between Lara Croft and Lucozade, the orange liquid that used to be thought of as medicine for the sick but reinvented itself through the 1990s as a sports drink.
The latest advert has Lara pausing for a friendly Lucozade with her enemies while the player's back is turned. This summer, in order to tie in with the feature film's release, Lucozade will be labelled "Larazade".
They probably call this "synergy", but it works because Lucozade is a product one can imagine Lara using, even if it is unclear where she might find a bottle in a dusty tomb. Jeremy Heath-Smith, the managing director of Core Design and head of global development at Eidos - who, despite Eidos's financial difficulties, was last year paid $3.5 million thanks to a long-standing royalty agreement - says: "The fact that it's a health-giving energy drink matched Lara's profile exactly. I'm not sure Irn-Bru could have the same effect, as nice as Irn-Bru is."
Lara is careful about who she's seen with, for obvious reasons. We can be confident that she would never endorse fruit-flavoured alco-pops, or depilatory creams. But the Lucozade partnership is a marvel of mutual reinforcement: association with Tomb Raider and Lara helps to sell Lucozade
In his novel Idoru, cyberpunk writer William Gibson imagines Rei Toei, a Japanese-engineered virtual celebrity who rebels against her makers and plots to find herself a physical body. In fact, the Japanese did have a virtual media star in 1997. Software programmers collaborating with Japan's leading modelling agency, Horipro, created Kyoko Date, the world's first digital pop singer. But sales of her debut CD did not live up to expectations. Why? Her face was a combination of features mapped from photographs of famous models; her singing voice was taken from one woman, her speaking voice from another; and her dance moves were digitised from the performances of real dancers. She was far more detailed and "realistic" than Lara Croft was at the time - but in a sense, Kyoko Date looked too real.
Our idoru does not fall into this trap. Lara Croft is attractive because of, not despite, her glossy blankness - that hyper-perfect, shiny computer look. She is an abstraction, an animated conglomeration of sexual and attitudinal signs - breasts, hot pants, shades, thigh holsters - whose blankness encourages the viewer's psychological projection.
Beyond the bare facts of her biography, her perfect vacuity means we can make Lara Croft into whoever we want her to be. If the computer-generated Lara Croft ever became too photo-realistic, too much like an individual woman, says Heath-Smith, "you'd lose some of that feel for her". The plans to finesse the character design for the next-generation Tomb Raider game, coming to Sony's far more visually powerful PlayStation2 some time next year, are "to smooth her off without changing the aesthetics that work".
But will these aesthetics be influenced by the performance of Angelina Jolie in the Tomb Raider film? Lara's creator, Toby Gard, rather approves of the casting. "Yeah, Angelina Jolie certainly looks the part," he says. "She has that certain wild quality which is important - that's what I had in mind." Jolie, we are told, performed most of her stunts; emulating the acrobatic, gravity-defying grace of her digital counterpart in the unforgiving real world resulted in injuries to her knee and shoulder and torn ligaments in her foot.
Bear in mind Lara has already been impersonated by several flesh-and-blood women without danger to her virtual hegemony - the models and actresses Rhona Mitra, Nell McAndrew, Lara Weller, Lucy Clarkson and Vanessa Demouy have all stepped into the boots for promotional appearances. Lara Croft, the virtual character, is the Platonic ideal: a human actress can give a better or worse account of that ideal, but she can never embody it fully, still less outstrip it. In that sense Lara is more like a creature of time-fogged legend than a contemporary "personality".
The rise to ubiquity of Lara Croft came as a surprise to her digital dad. "I never expected to have that happen," Gard says. "You know, as a designer, I'd gone through my life making sketches for these characters, and you think they're yours - then you realise they're not yours at all."
It was the massive success of Lara, in fact, that prompted Gard to leave Core Design and set up his own company, Confounding Factor, before the second Tomb Raider game appeared. "Other people were just doing things with her I didn't agree with," he says, guardedly.
He is working on Galleon, a game he promises "will have the same effect as Tomb Raider had in terms of how far ahead of everything else it's going to be".
It will be interesting to observe how Lara Croft ages. If the franchise is still going in 2020, will she be raiding tombs at the age of 42? There seems no reason why not. What allowed Lara's extraordinary success, after all, was the fact that Gard had created not a singular female character but a new archetype: an image so fluid and malleable that she can cross media barriers without appearing to whore herself.
Odd as it may seem, Lara has never been a primarily sexual being. In the immature world of video games, Lara was a revelation. In contrast to the standard near-pornographic portrayal of helpless women characters, Lara was a Germaine Greer of video games. Sure, she showed some skin, but her wardrobe was practical, rock-climbing, tomb-raiding stuff: shorts, hiking boots, vest, backpack. Gard says this was a deliberate reaction to the digital representations of women around him at the time, which persist today: spangly thongs, S& corsets, strange spirally metal bras.
"I wanted to make sure it wasn't the thigh-length boot-style stuff," he says. "You can't get emotionally involved with a character like that because it has been objectified. Lara, I felt, had more dignity." It wouldn't make any sense, you understand, to describe the dignified Lara as a sex symbol.
Because "sex symbol", if that overused phrase means anything at all, must mean a person with whom you can imagine having sex - however improbable that may be. Angelina Jolie may be a sex symbol. But Lara can't be. It is in principle impossible to have sex with Lara Croft: she is always and forever unattainable.
And, as we have seen, there are far more overtly sexual depictions of women in video games. So all the prurient fans' artwork - the notorious "Nude Raider" images created by boys disturbingly skilled in computer-aided imaging and posted on the net, and all the leering over Croft's breasts in the chat rooms - these are incidental, a predictably perverse subculture of the fan base, not its raison d'etre.
It seems probable that men who like Lara don't want to have her; they want to be her. That's why they play the game. Lara is a symbol, if anything, of aspirational gender reassignment. In both directions. Men who like trying on a female persona, or women, such as Jolie, who like doing what is usually thought to be men's stuff. To paraphrase Damon Albarn of Blur, Lara works for boys who do girls, or boys who like girls who do boys, or girls who do boys.
And perhaps it is this all-things-to-all-people, don't-you-dare-try-to-pin-me-down quality that has ensured her longevity. For it is axiomatic that the jumping, rolling, sprinting Lara Croft is physically inexhaustible. What is surprising is that over the five years of her career so far, she has also proven inexhaustible as an icon.
Steven Poole is the author of Trigger Happy: The Inner Life of Videogames (Fourth Estate, £12 in UK.