Mother-of-two Helen Miller, 38, was called at 1.30am and travelled with her mum to Freeman Hospital, where doctors believed they might have found a match.

But the emotional rollercoaster began a sharp descent when they arrived at the car park, and received a phonecall to say the lungs were not suitable for transplant after all.

"You go through so many different feelings it's hard to describe," said Helen, of Hawthorne Avenue, South Anston. "It's the full scale from being tense, to apprehensive, to excitement and being nervous."

"It feels like every single emotion at once. Getting that call could be the start of a new life for you, but you just don't know, no one does."

"I might be saying goodbye to my kids and husband for the last time, or I could walk back through the door a different woman."

Helen was given just weeks to live after being hit by an ultra-rare auto-immune disease in her teens. Defying doctors' forecasts, she was able to marry, start a family and work without difficulty until six years ago.

Tests showed her need for a transplant, and she admits there has been a steady deterioration in her health since. But rather than shake her faith, the recent false alarm has left her in an admirably positive frame of mind.

"I was encouraged that I'd had the phonecall," she said. "There's a possibility that there's someone out there. But on the flipside, it just wasn't meant to be for me this time."

But the shortage of donors means the wait is a long and painful one. Helen recently suffered a bout of depression, but says the support of people she has met through the hospital has been invaluable.

"I've got two very, very good friends, Diane and Louise, who are both also waiting for transplants," said Helen. "One has even had 10 phonecalls to say a donor may have been found, but she's still waiting."

"They are in exactly the same position as me. Every time the phone rings, you thing it's the hospital."

"We email each other a lot because there are things we can share that you wouldn't tell anyone else. Things about the depression we go through, not wanting to wake up the next morning, and other things you can't even tell your mum or your kids."

Husband John, 43, and children Abbie, 18, and 15-year-old Daniel offer support at home. Mum Pat Eaton, 62, lives nearby and her home offers a change of scene.

The publicity Helen has sought for organ donorship and NHS organisation UK Transplant has even seen her recognised in Asda. Barnsley resident Malcolm Cooper, 61, spotted Helen when her plight was featured on regional news show Look North.

After years of misdiagnosis and 12 months on the waiting list Malcolm had a successful lung operation in 1992 when such surgery was still in its infancy.

"Having been through a similar journey, I thought I might be able to offer some support and encouragement until Helen gets 'the call'," he said. "I occasionally I try to reach out to help because I'm so moved by the courage of people. Having experienced a particularly traumatic time myself I can readily empathise."

"Helen copes well and as I'm getting to know her I can see that she has that essential fighting spirit that will take her forward through these incredibly difficult times."

Malcolm, now a granddad-of-two, added: "Shortly after transplantation I walked form Ilkley to Lake Windermere, eighty five miles. Previously I couldn't walk 10 yards without being totally breathless. I was given the opportunity of a second chance because of the generosity of a young man who carried a donor card."

Helen needs round-the-clock oxygen, and said after years of wearing the equipment she is finally comfortable with people staring. She said people approaching her and asking about it has the same effect as her online diaries.

"Mostly it kids who don't understand," she said. "Staring is just a way of dealing with it. But if people come up and ask me about it, it gets people talking about it which can only be a good thing."

"It needs to get to the stage where organ donorship is thought of in the same was as blood donorship."