For me, exploring is a compulsion. It's a need to make my mark, and to prove to myself that when I'm up against all nature can throw at me, I can survive.

I didn't tell anyone about this last trip — not the media, not even my wife — so there was no ego in it. I'd done the Seven Summits and the North and South Pole, but however you cut the cake, someone had done those things before. Okay, some of my trips were unique in that they were solo, but they were still going over old ground. This was different. I was covering a new route to the geomagnetic North Pole, climbing glaciers and waterfalls, pulling my own sledge. No companions, no dogs, no supplies airlifted in.

I suppose it was mad, but I had to do it.

The first time I attempted to reach the geomagnetic North Pole, 20 years ago, I broke some ribs. The second time, in 1997, I wrecked all the kit and had to give up. I had no idea if this route across Ellesmere Island could be done, but I had to get it out of my system. It was the ultimate challenge: I would live or die by my own skills, by my navigation skills, and by my ability to feed and look after myself. I spent weeks obsessing over the equipment. I had a full climbing kit, crampons, ice axes, plus what I needed to eat. My wife knew I was going to the Arctic to do some polar training but she had no idea what was really going on.

I flew from Heathrow, went up through Ottawa, and was taken by a tiny plane to a little weather station called Eureka. The only safety measure I had in place was that I arranged to call the station every couple of days. It was about 30 degrees below when I set off and I felt trepidation, but not fear. I knew I'd be encountering huge cliff faces that are not marked on the map, and I never knew if they were going to be passable or full of crevasses.

On a polar trip you get into a rhythm. You walk so many hours, then you put up your tent and cook. But on this trip no two days were the same. I was skiing or climbing, crossing glaciers 100ft high. Route-finding was difficult — scary, as I only had enough food for so many days.

The Iraq war was just starting, and when I rang the weather station one day there was a message for me: "Would you like to comment on the death of ITN reporter Terry Lloyd?" Terry and I were mates, he'd covered lots of my trips, and my first thought was that he must be in a bar somewhere. Then reality sank in and I felt dreadful. I started thinking about all the loved ones who'd died. All the friends who'd been killed on trips. I completely lost it. I started thinking about my wife and children, which I never do when I'm away — I cut them out completely. But I couldn't stop it. I found myself obsessing over how they'd feel if anything happened to me. And for what? A stupid challenge.

I felt like a selfish bastard. Terry also had a family, but at least he'd died doing his job. Here was I, actually seeking danger.

You can't go down this route when you're alone. I was getting depressed and I really had to fight to get a grip. I'd already crossed a couple of glaciers and was crossing a series of frozen waterfalls of beautiful, hard ice. But the ice was unstable, and a sheet came off in my hand. I jumped 20ft onto what I thought was a pile of powder snow, but it turned out to be rock-hard ice. I'd snapped my ankle. The pain shot up through the top of my head and I was literally retching in agony. I thought: "F***. I've done it now." It was a couple of miles to the end of this waterfall and maybe another 40 on foot before a plane could reach me.

My foot was swollen to twice its normal size. But the most dangerous thing was the cold. I had to get the tent up and get some hot fluids inside me, but because I was on ice, there was nothing to get the pegs into. I had to rig it up with a ski pole and the sledge.

The next morning, I strapped my foot up and took a pile of Nurofen. It was horrendously painful. I was on my bum for almost an entire day, trying to lower the sledge and all my kit down this waterfall. By that night I'd made tiny progress and I thought I'd had it. The next day, I came out onto pack ice and that made things easier: I could ski quite well, as long as my foot was straight.

But I was running out of food and having to ration myself. For the last five days I lived on tea and pieces of chocolate. My leg was black to the knee. My head was filled with the things I normally try to keep out: my wife, my family, Terry. This was my retirement trip. The culmination of 25 years of polar travel. When the plane came into sight, I felt terribly emotional. It was the end of a chapter, and it wasn't how I'd imagined it. I didn't feel elated, I just felt sad and relieved that I'd overcome the problems. I felt I'd only got through it because of Terry, and I dedicated the trip to him.