Pam Warren is a woman who has defied the odds.

When a fireball ripped through the first class train carriage she was sitting in at 8.11am on October 5, 1999, the chances of her survival were slim.

Minutes later as she was crawling underneath the wreckage of the Thames Train and First Great Western which had collided, with diesel dripping on her head, the future looked impossible.

And as doctors battled to heal her burns in Charing Cross hospital they couldn't be sure Pam would make it through.

But she did.

Pam Warren is a survivor.

Now 47, and living in Pangbourne, Pam has told her incredible story in a new book From Behind The Mask, in which she speaks candidly about the crash which changed her life.

Pam was just 32-years-old when she boarded the London bound First Great Western at Reading. A financial advisor living in Bradfield South End and working for her own company, she was living the high life, swapping the latest BMW for a Mercedes after a year and enjoying a 'work hard, play hard' lifestyle.

She was studying for her advanced financial certificate and on her way to a training day, which fatefully, had been moved to London from the Thames Valley because there were not enough people from the area attending.

"It was a cold, crisp, blue sky day and I remember standing on the platform with my eyes closed thinking 'gosh, this day is lovely'," says Pam.

The train pulled up and carriage H, the first class carriage, stopped just in front of her.

"I remember thinking that's lucky," she says with a sombre smile.

After taking her seat opposite a man who, unknown to her then, was Keith Stiles of West Reading, she did a bit of paperwork before sitting back and watching the world go by.

"Then we got to Ladbroke Grove and I always remember that it was the screeching first of all," she says. "For a second I thought someone has pulled the emergency cord. It was that sharp, grinding metal on metal sound.

"Just as I was thinking that, I must have looked at Keith, and I realised I was looking down at him. Both of us registered it. His face and my face, and it must have just been a look of 'oh my God'.

"That was when I realised something was wrong."

The Thames Train which had left Paddington Station at 8.06am had collided nearly head on with the First Great Western at a combined speed of 130mph. Thirty-one people lost their lives and 400 were injured.

"It was just mayhem," continues Pam. "The carriage started bucking all over the place, we were being knocked around and it went dark. "There were brief cases falling down and all I could think of doing was grabbing hold of the seat and making myself small.

"That's when I looked over my shoulder and saw the fireball. It was probably only a second but it was enough for me to think 'I'm dead'."

The fireball tore through the carriage, leaving Pam with excruciating burns to her hands, face and legs.

"It did look like a movie special effect," she recalls. "I remember seeing yellow and orange and black and it was making this God almighty noise. I remember hearing men screaming which still upsets me.

"I had my hands up while it was going over and I have never been able to describe the heat. It's just impossible."

Immediately after the fireball had passed through Pam says there was a quiet in the carriage.

"I took my hands down and didn't realise how badly burnt I was. My leg had gone over the edge of the seat so it took the force of the burning, and it was still on fire. I put my hands down to put it out. Then I was over come by panic and thought 'I have to get out'."

Heaving herself out of a broken window Pam escaped from the wreckage, finding herself trapped in the middle of the 'v' shape with the two trains on either side.

Another survivor who had come from the buffet cart, helped her crawl under the Thames Train to safety.

"I think you go into survival mode. I think panic or getting upset or even registering hurt is ignored. Your brain goes 'I have got to survive'.

Sitting on the side of the tracks, Pam was comforted by other survivors who sprinkled water on her hands and hid the horror of her injuries from her. She would later be mistaken for another survivor, Evelyn, at the hospital, who had given Pam a jacket with her own ID badge in it.

After the ambulances arrived Pam was hoisted up out of the crash site on a pulley system, to a car park where survivors where being gathered.

"I remember, again just for a second, taking in the train crash, all those bodies laying around and my brain just went 'don't take it in, you have enough to deal with'. I shut it out."

Following the crash Pam was in a coma for three weeks while doctors added skin grafts to her hands and face. Although unconscious, Pam's survival instinct seemed to kick in and she continued to defy the odds.

"There was a bit of a scare because I was still in intensive care and there was some sort of virus going round," says Pam.

"If I got an infection on my wounds that could have seen me off. I caught double pneumonia too. I was not supposed to pull through."

She then spent another three months in hospital, undergoing painful physiotherapy and trying to come to terms with what had happened.

"They said I would probably get about 50 per cent usage back in my hands but I had to work hard.

"It took two hours to get the bandages off then when I saw why hands it was shocking. They didn't look like hands. It was like something out of a horror movie. But I had to do it. Even with the pain, I wanted more than 50 per cent."

It was more than a month after the crash that Pam saw her face for the first time.

"My doctor Nick [Percival] came up one evening and said, 'have you looked at your face?'," she recalls. "I said no, and he said 'you have to, and the time is coming close'.

"I waited until the next day when my family were not there and I went into my bathroom and I remember looking down the sink and there was a mirror and I gradually lifted my face to look at myself.

"I was horrified. It was just a mess. Even after six weeks it still was a mess. I just started crying.

"Afterwards when anyone came into my room I thought 'what must they be looking at'. That's when I started trying to hide my face, more so I didn't upset them."

It was her surgeon, Nick, who first suggested wearing the plastic mask which would help her skin to heal but would also become an iconic image of the crash.

Pam had been called as a witness to an inquiry into the crash and the day after her photo was on the front page of every newspaper. She became known as 'the women in the mask'.

"I went in on myself and refused to talk," she says, adding although she wasn't comfortable with the attention drawn by the mask, she realised it's importance.

"If the plastic mask needed to be the focus then that was it. It helped enormously in our campaign," she says.

In the wake of the crash Pam formed the Paddington Survivors Group to offer support to those who had been effected. The group took on greater significance as it successfully campaigned for better rail safety, helping to transform rail safety standards.

Although her work with the group was a focus in the months immediately after she came out of hospital, eventually the memories of the crash took over, and Pam stepped down in 2004.

She began having horrific nightmares of the crash but tried to hide them from anyone else until it all became too much, and she tried to take her own life.

"The suicide attempt happened when the nightmares and flashbacks were becoming overwhelming and I didn't ask for help," she says.

"As a result of it I had to have my stomach pumped and they wouldn't let me out of the Royal Berks until I was going to get help. I went to a clinic for people with psychiatric problems."

In her book Pam also talks briefly about the breakdown of her marriage, which happened several years after the crash.

Although she doesn't want to talk expressly about it, she says: "This is generic, but if you have a strong marriage and something like this happens you are going to work your way through. There must have been something wrong beforehand."

The nightmares and flashbacks she suffered in the years following the crash also triggered a period of alcoholism.

"I was having panic attacks and I didn't admit it to anyone," says Pam. "I was trying to cope and hardly sleeping. I started turning to alcohol to put me to sleep. I started with one or two glasses then a bottle and so on.

"That's a period of my life I'm very ashamed of. It is not who I am now or who I was before."

It was a meeting with Falklands war hero Simon Weston, through charity The Healing Foundation, of which both Pam and Simon are ambassadors, that helped turn things around.

"I went to visit him at his home in Cardiff and he said 'what would you like to drink?'. I asked if he had a glass of wine, but now I think he meant tea or coffee. He looked at me and started asking questions and he said, 'do you NEED a glass of wine?'.

"Admitting my problem to him was not as hard as it would have been to others. He was a relative stranger and I had a huge respect for him and he turned round and said 'Oh Pam, I have been there and done that'.

"To know it had happened to someone like that, I blurted everything out."

After putting that difficult period behind her Pam threw herself into work with The Healing Foundation, which works to support people living with disfigurement, and The Dame Kelly Holmes Legacy Trust which is committed to getting young lives back on track.

She works in project management and although not formally campaigning for rail safety, she still raises issues with the rail networks if people get in touch with concerns.

"Nothing can be 100 per cent safe," she says. "It's physically impossible. You have to accept there is a risk to catching a train, even I know that and I'm catching them now.

"But to me there is a level of unacceptable risk which is what was happening back then. If I stop catching the train, and I know a lot more about it than most, then people should be worried."

After travelling on a train in 2009 for the first time since the crash, during an appearance on Tonight with Trevor Macdonald, Pam now uses trains occasionally.

She some times travels to Paddington, always accompanied by a friend who assists her in the event of panic attacks which occur at times.

October 5, 1999 is a day which will always be part of Pam, she still has flashbacks of the crash and has to cope with the physical effects and Post Traumatic Stress Disorder.

But after everything she has been through, the Pam Warren today has a smile on her face.

"Writing my book has been helpful but mostly I have done it because this is my way of saying life is wonderful and don't give up.

"I didn't feel right writing it any earlier because I wanted to put hand on heart and say I am definitely through this, and I am."

From Behind the Mask by Pam Warren is published by Biteback Publishing on March 4.