In the 1980s, when her children were young, Diane Piper kept a diary of their progress. They were an ordinary family. The Pipers lived in a sleepy Hampshire village, where Diane was an infant-school teacher. Her husband, David, was a barber, and their children, Paul, Katie and Suzy, proceeded happily through karate and ballet lessons, kite flying and beach excursions. Katie was, by some measure, the loudest. "She was quite wilful, headstrong, very independent and made friends wherever she went," says Diane.
"You're being very diplomatic," says Katie, laughing.
The diary petered out, but four years ago she resurrected it, this time not for a happy reason. Diane was at the gym one day, when there was a call from David. They had to get to the Royal Free hospital in London, he said, because Katie had been the victim of a chemical attack. There was no other information, so they packed a bag and went. "We ran out of the house that night, not really knowing what we were going to," says Diane. Had someone thrown bleach at their daughter? Anthrax? Were terrorists involved?
The attack had, in fact, been planned by Katie's ex-boyfriend, and the substance thrown in her face was sulphuric acid. She had had to wait an hour in a cafe for an ambulance, screaming while the liquid burned down to the bone. When they first saw her in hospital, Diane, a quiet, unassuming woman, was stunned. "I think when you go into a state of shock, you go numb – I didn't cry." They were taken to the specialist burns unit, where, "They were treating her, trying to wash her face. There were people everywhere, tubes everywhere ... and we stood and looked, almost not believing it was Katie."
Disbelief is the natural reaction to the story, because of the severity of the attack and the extent of Katie's progress. When it happened, she was working as a model, trying to build a television career; while Diane knew her daughter was resilient, she worried about how she would cope. "Her whole career, her whole future, focused on her face, and that face was," her voice drops suddenly, "forever damaged. It's like a pianist losing their fingers, isn't it? You think, well, OK, she's still here, she's still alive, thank God – but you couldn't really see what was going to happen after she left hospital."
Katie describes the attack and its aftermath in her gripping memoir, Beautiful. She was in her early 20s, living in London, appearing on late-night TV shows – "working on the DIY channel," she says, "selling cordless kettles" – when she was contacted by a man called Danny Lynch on Facebook. They had 30 mutual friends on the website, so he seemed credible at first, and after he bombarded her with lovely messages she started to see him. He told her he was a martial arts enthusiast who owned property and was also studying computing.
Before long, she began to doubt his stories and had resolved to break up with him. Then he raped her. He threatened to harm her or her family if she told anyone. In the following days he continued to call and text constantly, until the moment he implored her to go outside, to an internet cafe, to pick up an email he had sent. An associate of his, Stefan Sylvestre, was waiting in the street and the acid he threw in her face led to the loss of her eyelids, most of her nose and part of one ear. Her face had to be cut away entirely, in the first of almost 100 operations.
Sitting on the sofa beside Diane, it's only Katie's slightly defensive posture – knees against her chest, arms wrapped around them – that betrays the impact of what happened four years ago. With her tumbling hair and towering heels, she is exceptionally glamorous and her career is thriving. She has a two-year deal to make programmes for Channel 4, writes a column for the weekly magazine Reveal, takes acting classes as a hobby and runs a major charity for fellow burns survivors. She has proved to be an excellent, articulate advocate for their cause.
As a result of TV appearances, including a documentary on her story, she often meets people who ask how she survived the assault, which was clearly intended to obliterate her. In response, she has written a guide for people in traumatic situations, Things Get Better. Katie finds it embarrassing when people praise her: "There was no way I could have gone home, lived on my own and got through it all. It was a group effort."
She and her mother talk every day, and their close relationship is obvious when they discuss the book at the start of our interview. Katie tells Diane, for the first time, that the book is dedicated to her and David. Diane silently rolls her eyes.
"Oh thanks!" says Katie.
Diane blinks with surprise.
"Oh, you mean really? Seriously? Oh right. I thought you'd have dedicated it to all the people who have helped you."
Katie hoots at her mother's modesty. "The first one was dedicated to my doctor and I thought the second one should be dedicated to you."
"Ah, how nice," says Diane, clearly still confused by the idea that she has done anything extraordinary.
Diane and David stayed at the hospital for seven weeks to be with Katie. The outlook was bleak. On a high dose of morphine in the days after the attack, Katie wrote a note to Diane asking her mother to kill her. She had to wear a mask made from skin from donor corpses for 10 days, before an operation in which the dermal substitute Matriderm was applied to her face, as a foundation for grafts from all over her body. Then she was put into an induced coma for 12 days (the pain would have been too extreme otherwise). There were times in hospital, says Katie, when her eyes were open, but she thought she was, "on a ship, or in a prison, in another country. All these weird hallucinations."
Diane started a diary of Katie's progress, and also took photographs. "I wanted to show her that this wasn't the end. This was just the beginning, and she would get better. And there was the proof."
She could tell her daugher: "There's the photo of you a month ago – and look at you now."
The pictures helped enormously, says Katie. She could look at them and think, oh, the redness has gone down. Oh, I can move my face more ... If I ever felt depressed when the treatment had finished, I could look at the photos and think, I've come so far."
The attack left Katie partially blind in one eye; Diane and David both offered to donate their eyes and skin, but were told it wasn't possible.
After Katie left hospital, and came back to the family home, she had to wear a plastic mask, and her sister Suzy offered to wear one too, in solidarity. Suzy also hid notes all over the house, telling Katie how much she loved her. Her brother Paul tracked down Pam Warren, who suffered severe burns in the Paddington rail disaster in 1999, and had also worn a plastic mask, arranging for her to visit them. She turned up with a friend, "We didn't know which one was her!" says Katie.
Diane nods: "That was a big boost for the whole family."
Diane and David had to massage Katie's skin four times daily, while struggling to keep her spirits up. She was terrified at first, fearful of being burned or attacked again, of going out in public. It was as if she was a child, needing to be reintroduced to the world.There were many times, says Diane, when she felt helpless. "If Katie's upset then I get upset – if she cries, I cry," she says.
"There were times when Katie would be feeling low, and she'd say, 'I hate my face'. You feel helpless as a parent because you can't fix it. But mostly she was very upbeat."
The treatment Katie's plastic surgeon, Dr Mohammad Jawad, performed was revolutionary; she was one of the first people in the world to have a full-face Matriderm treatment, which Jawad has since been able to perform on women in similar circumstances in Pakistan. But despite its success, she still needs more surgery. The scars on her neck have contracted, so it's hard to turn her head.
"If, in a few years, my eyelids contract, they'll turn inside out. I have to have nasal reconstruction, for the septum and nostrils, to help with breathing." Her throat was damaged in the attack, so "my oesophagus narrows with scar tissue, and I have to keep having that widened."
Lynch and Sylvestre were both given life sentences. How does Diane feel about them now? "Oh, I don't really think about that," she says, "because it's wasted energy, isn't it? What's done is done, we can't change that, but we can change the way we cope with it."
There was a time when Katie thought she would never have a normal, happy life again but she is dating now, and looking forward to one day having children. When she does, she says she'll try to live up to Diane's example. "My mum has come to every operation with me. She's waited for eight hours, in a side room, with no chair, for me to go into surgery. She's come to foreign countries with me to have treatment, and not been able to speak to anyone. I really hope I can be like her."
Diane's eyebrows jump. She looks as nonplussed as ever by the compliment.
• Things Get Better by Katie Piper is published by Quercus, £12.99. To order a copy for £10.39, including free UK p&p, go to guardian.co.uk/bookshop or call 0330 333 6846
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