I was climbing without bottled oxygen. All my team mates and Sherpas were climbing with it, as was nearly everyone else from the other teams. In fact I can only think of three other climbers apart from myself on the mountain who were climbing without O's, the Italian legends Fausto de Stefani and Sergio Martini, both of whom have climbed all 14 mountains in the world above 8000m. (Only 12 men have ever climbed all 14) and their younger climbing apprentice, Roberto Manni. A few weeks earlier their Sherpa had been killed by a rock or block of ice at the bergshrund at the base of the Lhotse Face. I helped Sergio bury the body and clean up the mess, and we lent them one of our Sherpas.

The climb to Camp 4 without O2 was somewhat tiring and apart from my summit day on Cho Oyu in October 2006, perhaps the hardest day of my mountaineering career. 9 hours of constant up and across the Lhotse Face on sheer blue ice covered in about 2 inches of fresh snow. Crossing the yellow band at 7600m, I caught up with, and overtook Fausto Di Stefani. He was on his hands and knees on the yellow band, gasping for air, as I had also been during that one long day. Despite this I made reasonably good time to camp 4, arriving only 30 minutes to an hour after our fastest member. When I arrived I saw that one of our tents had not been set up and worse still, the tent's platform had been prepared either. At almost 8000m, on a pitch of around 45 degrees, it took over 2 hours to dig a ledge big enough to accommodate the small two person tent that I would be sharing with Dan. This was valuable time that would have been better spent resting and rehydrating. It was 7.30pm by the time we had finished. I was exhausted and dehydrated and as soon as the sun went down I would be freezing cold, and in less than 8 hours I would be setting out for the summit.

Not long after we crawled into the tent Pemba Doma Sherpa stuck her head in. She had asked us in Base Camp if she could climb with us, but she was not officially part of our team. Pemba Doma was the first Nepalese female ever to summit Everest and make it safely back down, and the first Nepalese female to summit Everest from both sides. We were very surprised to learn that somehow she had no tent and was intending to sleep outside just in her sleeping bag! This was extremely dangerous and unacceptable due to the altitude and the cold. So we asked her to share our tent. This meant that we were now 3 in a very small 2 person tent, and our gear including our boots had to be stored outside. I was not happy about the boots, and looking back on it I should have insisted they be kept inside.

By the time we had boiled enough water for the next day it was approaching 9.30pm. Dan and Pemba decided to sleep on oxygen on a 1 litre flow. Again I resisted using the O’s, and during the night I actually felt very good, with none of the headaches and sudden gasping for breath normally associated with this altitude. 

After an absolutely sleepless night due to the cramped conditions in the tent which left me pushed up against the wet, cold canvas on one side, the next morning we set out for the summit. Just before leaving I paused at the oxygen bottles stored outside the tent. With my acclimatisation to 7850m, I could easily take two bottles and almost guarantee myself a summit. Or I could attempt what I came for and go for the summit without using the juice. I kept to my original plan and left the bottles behind. However soon after setting out my toes started to get cold due to my boots having spent the night outside the tent. As I climbed above 8000m however, I surprisingly felt very strong, better than I had felt climbing up the day before despite the higher altitude, and most likely due to the extra red blood cells I had accumulated by climbing without O's above Camp 3 and not sleeping on oxygen in Camp 4. However my toes were cold. As I approached the Lhotse Couloir at 8100m my toes were very cold. I looked at my watch, and estimated it would be at least another 3 hours before the warming sun would reach my position. I pushed up again. 

I was facing a difficult decision. Do I continue or turn around? By now I could not feel my toes at all. I had spent 7 weeks getting here. I was around 400m and 6-7 hours away from summitting Lhotse without using oxygen. My lungs and legs felt strong and my head was clear. But my toes were freezing. Do I keep going or not? I pushed up again. Up ahead I could see someone descending. As they approached I saw it was my mate Will Cross, who was climbing with another expedition. He told me he had turned around due to cold feet. Will has climbed the 7 Summits and walked to both the North and South Poles. ‘The mountain will always be there’ he mumbled through his oxygen mask as he climbed down past me. He was right. I had seen first hand climbers who had pushed themselves too far and ended up either with severe frostbite or paying the ultimate price. I decided to trust my intuition and turn around, before being forced to by dire circumstances.

Reluctantly I turned around and started the long descent to camp 2 at 6400m.

Meanwhile, Pemba Doma Sherpa was approaching the summit of Lhotse at 8516m. As a Sherpa, she had inherited the genes over hundreds of years to enable her to climb high and fast at altitude. The bottled oxygen gave her an additional turbocharge that very few non sherpas could keep up with. At around 11.30 am she became the first Nepalese woman ever to summit Lhotse. But on the descent, at around 8400m, she slipped and fell over 900m to her death. As I descended I heard Dan above call over my radio ‘There's been an accident! Not one of our team! A Sherpa! Oh my God...was that Pemba Doma....?’ 

Thanks to Dan Mazur from Summitclimb and Thai International Airways.

Looking down the Lhotse Face and the Western Cwm from around 8100m on summit day. Pumori, 7167m in the centre of the photo with Cho Oyu, 8201m looming behind. In October 2006, I was standing on the summit of Cho Oyu looking in exactly the opposite direction. Shortly after taking this photo I reluctantly turned around.