Where compasses fear to point

In the beginning there were three of us: David, Rebecca and me. David Hempleman-Adams had just become the first Briton to walk to the South Pole, solo and unsupported. And like Rebecca Stephens and me, he'd climbed Mount Everest in 1993. Now, just days afterwards, he was suggesting something I knew was really stupid.

"Why don't you come, Graham?Rebecca and I are taking a yacht down to the Magnetic South Pole. No one's ever done both in one season."

This was madness. The Southern Ocean is a savage sea. How would we avoid hitting the icebergs? And what was the Magnetic South Pole, anyway?

Simply put, it's where all the compasses in the world don't point. An imaginary entity, it roams the seas off the coast of Antarctica as unpredictably as the albatrosses that live there. We'd have to locate it by satellite navigation, compasses don't work.

My motive for going was to see whether I was capable of achieving a long- nursed plan to sail non-stop around the world on each of the seven seas and climb the highest mountain on each continent: the seven summits. This has never been done before. Having climbed what are probably the two hardest mountains, Everest and McKinley, now it was time to try what is certainly the most ferocious of the seven seas.

So that's how we ended up on Spirit of Sydney, a 60ft aluminium retired racing yacht based in Hobart, Tasmania. This was like three yachties turning up at Everest and asking for a guided tour to the top. However, there were also three professional crew, as well as David's father-in- law, Ron, who was a proper sailor.

We attempted to leave land three times before the yacht was even half ready for sea. That set the tone. On the trip holes appeared in the soft metal of the hull - devoured by electrolytic corrosion, so the bilges started to fill with water. We felt sea-sick nearly all the time. The skipper had the three incompetent climbers under his eye on C watch. Somehow the mainsail ripped when half a ton of ice froze on it. All the fresh water in the tanks froze solid because we were sailing through sea-water at -1C. During a storm one night a wave came on board, cut some heavy ropes and stole the life-raft, not leaving a sign.

In my bunk, an 18-inch-wide bookshelf, I tried to sleep, not believing the violence of the sea. A vertiginous swoop of the bows. A susurration of water heard through the hull plates and slam! we hit a wave and slam! again. I hit the ceiling of my bunk so hard that for the first time in my life I sustained an injury in bed.

Cooking was an athletic process: dancing in front of a gas cooker, juggling with pans. Ron and I engaged in an unspoken competition to cook the most exotic cuisine possible at sea. We overdid this eventually and the gas ran out, resulting in a spirit stove being pressed into service.

But we got there. We landed on Antarctica, an ice-bound shore of penguins and eternal winds. We saw the hut where the yacht's owner and his wife had spent a year. We sailed for two sunny days, through icebergs sitting in a calm blue sea like a home fleet of dreadnoughts. And we found the Magnetic South Pole at three in the morning last 20 February. It seemed to be a patch of ocean much like the other 3,000 miles we sailed. But above our heads the Southern Lights shimmered from horizon to horizon like a vast green curtain hanging down from space.

And the best bit? I'll never forget the time we three Everesters were crouched in the cockpit in the last 65-knot gale. Violent storm force 11, it would have said on Radio 4. I was steering, the mainsail had just ripped for the second time, and we were careering down the backs of 45ft breakers. This moment was so exhilarating that everything seemed to be happening in a slow dream. Like climbing, the danger sharpens your senses to a degree you never experience in nominal life. It's sailing, so you're cold, wet and sea-sick. But you feel very, very alive.