Doctors asked Shahna Thwaites' parents to switch off her life support machine. They refused and, against the odds, she has recovered.
Shahna is an avid crossword puzzler who does not care which words she scribbles as long as they fill the gaps.
She is a former grade-A English literature student who has struggled through just one novel in five years - and cannot remember a word.
And she is a former school head girl who later dropped out of college because she could not stand the pace of two-and-a-half days a week. But her parents are immensely proud of her.
That is because Shahna is also a 23-year-old woman who recovered from a 23-day coma after doctors advised her family to switch off life support.
She has slowly learnt to walk and talk again in the five years since she was thrown from a car crash which killed two friends.
Now she is joining police for a Christmas road safety campaign aimed at saving others from the horrific experiences she has experienced but survived.
Shahna, of Church Lane, Barnham, was 18 when she was involved in the crash on the way home from the Glastonbury music festival in June 1997.
She and her parents, 51-year-old barrister's clerk Tristan and 54-year-old Lynda, candidly accept she will never again be the same bright, outgoing girl she once was.
They describe the past five years as Shahna's "second childhood" as she struggled to become a functioning human being again.
She is still partially paralysed down her right side, as indicated by a drooping of her right eye.
The brain damage she suffered has blunted her intellectual capacities and her short-term memory.
But Shahna is fiercely determined to remain as independent as possible, often interrupting her parents when they try to speak on her behalf.
Shahna was one of five Sussex students returning from the festival when their car overturned in the fast lane of the M5 near Bristol.
Nicola Cripps, of Milton Road, Peacehaven, who was driving, and Jeremy Wood, of Queen's Road, Brighton, died. An inquest heard the group had taken cannabis, speed and LSD at the festival. None of them was wearing a seatbelt.
As soon as they heard their daughter had been seriously injured, Tristan and Lynda drove through the night to the Frenchay Hospital in Bristol.
When they arrived at 2.30am, surgeons told them no human being could survive the sort of brain injuries Shahna had suffered.
Hospital staff believed she would be dead within two hours. But Shahna clung to life.
Her parents refused to consider switching off her life support machine and between them maintained a 24-hour vigil at her bedside in the intensive care unit.
Tristan said: "We were told many times we should give up the struggle and let Shahna slip away. But there was no way we could do that."
They realise the doctors were just trying to be kind as the swelling on Shahna's brain steadfastly refused to go down.
But her parents talked constantly to her, trying to will her awake, until a whispered greeting from her father finally seemed to have an effect.
As he leant over her face to say hello, he noticed her top lip quivered. He immediately called over the doctors, who said: "We'll put that down as a smile."
Shahna said: "My dad always made me smile. I reckon that's why I came out of it so well - because while I was in the coma I was constantly being talked to."
During the following few days, Shahna gradually showed more signs of life. Her eyes opened and she started to move her fingers.
As her strength very slowly returned, she returned to the family home in Yapton on October 17 but spent much of the time sleeping.
She was confined to a wheel-chair until July 1998, when she took her first faltering steps, little more than a year after the crash.
In the coming months she regularly attended Arun Leisure Centre, where manager Stephen Luckham drew up an exercise programme for her.
Lynda also spent hours with her, throwing a rubber ring back and forth to strengthen the muscles in her arms and improve her co-ordination. Shahna still needed plenty of help, such as climbing upstairs to bed.
The fact she had gained three-and-a-half stone since the accident made things harder but gave her extra motivation to exercise.
Her family managed to raise enough to send her to the Queen Elizabeth Foundation Brain Injury Centre at Banstead Place in Surrey, from September 1999 to the following July.
As well as helping her walk better, staff there had to help rebuild her social skills as she had lost her inhibitions and tolerance.
She often had tantrums, screaming at her family in the middle of the street and using obscene language.
Shahna said: "I look back on that time and I just cringe. I cannot believe I did that sort of thing."
Tristan said: "Shahna lacked a lot of social awareness and that could have made her very vulnerable. People had to take great care to ensure she came to no harm."
Before the accident, Shahna had been a grade-A student. She had been head girl at Great Ballard School in Eartham, near Chichester, before starting her A-levels at Brighton Technical College.
She was studying English literature and media and wanted to become a television journalist.
Her father said: "She was also an outgoing, happy young lady - fiercely independent and very able to look after herself. She was very advanced for her years."
On her return home from Banstead Place, Shahna started a part-time photography course at Chichester College.
She lasted for a year, attending two-and-half-days a week, before realising she did not have the strength and concentration to continue.
Instead she decided she would prefer to concentrate on photography as a hobby as well as writing on her computer.
Her ambition is to publish a book recounting her experiences, based on diaries and poems she has recorded since the accident.
While her father describes many of her early writings as "teenage angst - asking, 'Why me?' all the time", Shahna insists she wants them to be published to show her progress.
Whereas she used to devour classic novels, now she can only manage frothy magazines.
Shahna said: "I did read all the way through a girly fiction novel on holiday in Cornwall. I was pleased to reach the end but now I can't remember anything about it."
Her love of crosswords is affected by her inability to remember the meanings of many words.
Her family has had to crack the codes of her odd phrases and words, such as when she would ask for a drink by requesting an "NCP".
Tristan said: "I often see her curled up with a crossword but when I look at it afterwards the words she has used bear no relation to the clues.
"Often it feels like she has entered a second childhood, though this one has been packed into five years instead of 18."
The family is building a two-bedroom extension to their home, paid for out of the £1.8 million Shahna received in a legal settlement last year from the estate of the dead driver.
As well as the continuing problems with her memory and co-ordination, Shahna has a valve running from her brain down to her stomach.
It is there to drain off excess fluid her brain produces, which could plunge her back into a coma.
Her desire to remain active is partly responsible for Shahna's involvement in a Hampshire Police campaign on road safety in the run-up to Christmas.
Next Wednesday she will attend the launch of the campaign, which asks people, "Are you fit to drive?"
It warns them not to get into cars with drivers under the influence of drugs or alcohol.
Shahna is particularly concerned to stress the importance of wearing a seatbelt, which could have reduced her injuries significantly.
Her parents also believe festival organisers should provide stronger checks on whether revellers are fit to drive home at the end of events.
She said: "I try not to think about the accident. Almost every day I think, 'Why me?' But I'm not going to let anything get in the way of my recovery."
Tristan said: "At times I find myself dwelling on what was going through her mind as she was flying through the air. That is a personal nightmare of mine.
"But wondering why this had to happen to us is a useless question, which doesn't help us forge forward with rebuilding our lives."
However, the family did pay a return visit to the Frenchay Hospital last week, where staff were still unsure how Shahna pulled through but were full of admiration for her strength.
Shahna's plight fills her family with mixed emotions - delight and pride at her progress, sadness and frustration at her continuing suffering.
That double-bind expressed itself when Tristan, prompted by another interruption from his gregarious daughter, exclaimed: "Sometimes she does my brain in!"
The agonising irony of the phrase may have been intentional or merely instinctive. But the words left his lips with a rueful, fond, bittersweet smile.
Shahna's story features in the programme Meridian Focus on ITV at 11.35pm on Friday.
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