BBC News Online health staff
Gill Brown is terrified of flying and had not flown for 12 years when she spotted the challenge of a lifetime - a chance to ride a sleigh of huskies through the Arctic.
Gill travelled about 70kms each day
For most people getting fit enough to tackle such an arduous race would prove to be challenge enough.
But Gill, a TV producer from North London, knew that no matter how well she prepared, she would only be able to take part if she could overcome her phobia.
She had four international flights to face just to get to her destination and the same on the return flight.
But she was so determined to take up the challenge that she decided to raise sponsorship for the Disabled Living Foundation and so reduce the chance she would back out.
"My fear of flying had got worse as I had got older.
I don't know why it happens. I get very claustrophobic and don't even like getting on the tube
"I had got myself into such a state that I once had to be taken off a plane on a trip to Canada.
"It had really hampered my life-style and my work."
Gill, 55, had tried a course to conquer her fear, but it had not helped.
"I don't know why it happens. I get very claustrophobic and don't even like getting on the London Underground trains.
Sledding proved tough work
"But when I saw this challenge, I knew I wanted to do it and it jumped out of the page at me.
"If anybody had said to me 'what would be your ideal holiday?' I would have said it would be to go to the Arctic."
Gill raised over £4,500 for the Disabled Living Foundation from friends who were keen to encourage her to take up flying again.
"I had this image of myself on a plane. I thought you only live once and I thought that I could not think of anything more exciting than going to the Arctic and I thought that if I die, so what."
Even though she had made up her mind to fly, Gill was still nervous and took a valium before boarding the first flight to Sweden.
"I was very nervous when it took off and needed to have a brandy as well.
"But when we came into Stockholm it was very windy and I just freaked out and the airhostess had to take me to the back of the plane and hold onto me."
A doctor on the trip had to give Gill another valium and she spent the second flight to the Arctic clutching onto the doctor and screaming.
But when she reached her destination, the trip was everything she had dreamed about.
"It was extraordinary. It was physically challenging, because you go about 70-75 kms each day.
"There are lumps and bumps and you have to go up and down hills.
"And then when you get to the hill you have to get off your sleds and help the huskies."
But after a fantastic trip it was back on the plane for another nerve jangling flight home.
But will Gill fly again?
"I feel that I ought to try and get on a plane to somewhere like Paris, but I don't think I will.
"If there was a trip again to somewhere like the Arctic though I would try to go."
Dr Francis Lillie, a clinical psychologist involved in the Aviatours' 'Fear of Flying Course', explained that many people share Gill's fears to some degree.
"One in four people are anxious of flying in an airplane, because they have to give up their control.
"They have to give their control to the air traffic controllers and the pilots and that exacerbates their feelings of being out of control."
He said the Aviatours course encourages people like Gill to face their fears by introducing them to cabin crew and pilots, talking to them about their fears and then they are taken on a one hour flight around Heathrow.
"They are encouraged to get on the airplane and there are very few of them who don't.
"They get individual help and they are encouraged to walk around the plane," he said.
A spokeswoman for the Disabled Living Foundation (DLF) said they had been very impressed by the way Gill had tackled her fears to raise their cash.
'Gill was such a source of inspiration to everyone on the trip.
"Not only did she sign on for the toughest fundraising event the DLF offers, she faced the physical challenge of dog sledding over 250 km in rough terrain with temperatures averaging -15 degrees Celsius, only having to face her momentous fear of flying before we even left London!
"Needless to say, she faced her fears with courage and conviction, proving to herself that she is capable of anything."