In the past few weeks I think I’ve experienced more highs (and lows) than I have in a very long time. Sailing into Peggotty Bluff at the end of the Southern Ocean crossing was a definite high, but realising the weather would hold us up from starting the land crossing of South Georgia Island brought us back down to earth with an almighty thud.

With the weather working against us, we had no choice but to wait it out, a prospect as unappetising as a bowl of pemmican, but really the only choice available given the circumstances.Waiting for a good weather window is a strange game to play, as conditions down here are difficult to predict and can drastically change minute by minute. Knowing this, after waiting for days camping on the seal-lined shore and sheltering in a cave, we set off in conditions that were less than perfect, but better than anything served up in the days before.

Attempting a climb like the crossing of South Georgia on the back end of an 800 nautical mile sea journey in a little, wooden rowboat adds another dimension to the climbing: the burden of fatigue. Most mountaineers typically start out fresh, not recently beaten up by the Southern Ocean!

With three key crew members acquiring painful medical conditions associated with extended exposure to cold, wet and cramped conditions, they weren’t able to join us on the traverse. It was a bit of a cruel blow for them, as they had all proved themselves to be outstanding members of the team and still desired to continue the journey. Shackleton too had to leave some crew members behind for fitness reasons before attempting the crossing – yet another parallel between his journey and ours.

So it was left to myself and Barry ‘Baz’ Gray (both wearing and using traditional gear) and Paul Larsen (in a supportive role wearing modern gear) to get over the glaciers for the team. Barry ‘Baz’ Gray, a mountain instructor with the Royal Marines, couldn’t have been a better person for the job. His experience and knowledge of mountaineering is unquestionable, thus the role he played was crucial. Baz is like an engine room, he kept us chugging along and focused on the finish line. Paul Larsen proved himself to be an invaluable asset on the climb also. Not only did he share the load, his presence lifted us at a time when a morale boost was needed and his return to the equation was a pivotal part of the journey and a real turning point for us all.  When Paul rejoined the climb, Baz and I had just spent 24 hours pinned down in a tent on the ridge atop Shackleton’s Gap with winds raging at 80 knots – the other tent blew away and we struggled to keep our gear and ourselves grounded in the extreme blizzard conditions.

We managed to complete the expedition by breaking the trek down into small goals – making it to the next ridge, the next valley, the next point on the journey was our focus. Using this simple yet effective approach, the goal of getting to Stromness slowly became more tangible with each metre we walked. Our endurance was tested time and time again, but we just kept pressing on through the blinding rain, snow and winds strong enough to knock you over.

Patience is required in this type of unforgiving environment. It’s a place where glaciers can move and crumble beneath you, crevasses can be hard to spot in low visibility and the non-stop noise of the wind can send you balmy.    We fell down to our knees and higher into crevasses at least 20 times as we crossed the Crean and Fortuna glaciers.   We were roped together and that’s all that stopped Baz disappearing down a bottomless crevasse when he fell into one of the hidden traps up to his armpits.  It took Paul and I all our strength to haul him out.

Thankfully, the conditions improved significantly on what turned out to be our last day on the ice and although the infamously wild winds still blew with intensity, at least we had some sun and warmer temperatures to help us make headway. In the last few hours of the climb we were dealing with fatigue on fatigue, literally layers of cumulative fatigue acquired over the past few weeks weighing heavily on us. My boots (vintage boots with screws nailed into the soles) were a wet, painful prison for my battered feet and my period-era clothing was so dirty I’m surprised it didn’t get up and walk off on its own accord!

Our arrival onto the shores of Stromness in the setting sun was dreamlike. Seeing the faces of our original crew, support team and film crew standing on the shore was a relief, as was the chance to take my boots off! Now that I’m back on board the support vessel again, fed, showered and rested, I’m finding it difficult to believe that this epic expedition is behind me.

For the past four years it has occupied such a big part of my life, it’s taken on a life of its own. But instead of being this big thing ahead of me, it's now behind me, and it's a huge weight off the mind. Although the physical part of the expedition is over, I know I’ll be talking and writing about this epic ‘double’ journey for years to come. It’s been with me for four years, it’s an entity I’ve grown accustomed to and one which I’m not quite ready to let go of just yet. Just like Shackleton, I’ve got expedition fever which I’m not sure I’ll ever completely rid myself of.

Tim Jarvis, The Shackleton Epic expedition leader, as told to Jo Stewart on support vessel the Australis.