I am sitting in my tent, 26,000 feet up on Mount Everest, and someone comes to tell me that a Swiss climber has died in the next tent.

Having spent the previous two years of my life preparing physically and mentally for this challenge (as well as the past eight weeks living in the Himalayas, climbing up and down higher each time, acclimatising to the low levels of oxygen) hearing information like that can make or break you.

It is May 22, and my climbing partner Graham has to pull out as he's cracked two ribs due to the infamous Khumbu Cough many climbers experience as a result of the dry air.

I have eight hours to rest at Camp Four before I take off into the death zone. We set out that night at 10pm, walking across Everest's South Col in the dark. I was accompanied by my Sherpa who climbed behind me, driving me forward.

It was -40ºC - but with no wind - as we began our journey to the summit. Each step was very difficult, and catching your breath at these altitudes can seem impossible. Just beyond the Balcony, a wide slope at 27,500ft, the wind started to pick up and I was stopped in my tracks as the wind was driving snow into my face. I wanted to turn around. I was reminded of the high winds and storm that hit in 1996, when 11 people died in one day on Everest. I didn't want to get caught out.

The wind died down just enough to help me make the decision to move forward. It was still dark and I could see electrical storms over the horizon, as well as six head torches above me. I was with my Sherpa, but could see no other climbers behind me and wanted so much to get closer to the climbers above. I knew there was a Scottish climber, Martin, ahead of me and I wanted to catch him to relieve the feelings of being alone.

Every step was hard work, hour after hour, step by step, pushing slowly forward. About four hours later, I reached the South Summit of Everest and sat in the dark, sipping water.

As I got up to sort out my backpack I saw a dim light on the horizon. I spotted a climber standing close to the edge with a 10,000ft drop on one side and a 9,000ft drop on the other. This is a section known as the Knife Edge Ridge and it has killed more than 30 climbers.

My Sherpa behind me began to shout, "Stop, stop!"

The climber yelled back: "It's Martin. I'm blind."

It was terrifying. Martin had lost his sight due to a lack of oxygen. The Sherpa kept shouting over my shoulder for Martin to stop and wait but due to the lack of oxygen, we could not run over to help him, we could only slowly move to his aide. After 10 minutes we managed to manoeuvre Martin around us and on his way back to the South Summit, where he eventually regained his vision. I was scared, and had to get off this ridge as quickly as possible.

I was struggling and as I moved towards the Hillary Step I broke down. My Sherpa tried to keep me positive and focused on the fact that I was strong - physically I was feeling good and that was enough to reset my mind and help me move forward.

I climbed the Hillary Step and the ground became easier to cover. Seeing the summit in the distance for the first time was enough to push me to the top. I stepped up on the summit, a 20-foot ridge that is just two-feet wide, and took out my video camera so I could snap a few pictures. By then I was ready to get the hell out of there.

It was hard work, but slowly I kept moving down, back to Camp Four. My body and mind had held up to the rigours of climbing high on Everest.

After eight hours up to the summit and four hours back down, I reached Camp Four. With a release of emotion, I embraced my Sherpa, embraced Graham and Martin and cried. I was so happy to be alive, happy I had pushed myself past my fears and reached the top of the world. It was time to rest and refuel for the night. Ahead of us, was a two-day journey to descend to Everest Base Camp and then make the journey home.

Everest, A Summit Calling, a documentary on Ian's journey, is available from info@iantaylortrekking.com. Ian runs a trekking company leading trips to Everest Base Camp, Kilimanjaro and Machu Picchu. If you would like more information on any of his trips on offer, check out www.iantaylortrekking.com