Running has always been a passion of mine. I started as a child in the Yorkshire Dales, moving to cross-country at university, then graduating to marathons. I loved the challenge. After my wife, Stephanie, and I married in 2012, and went on to have two daughters, Grace and Rose, I still ran for pleasure, but competitive events took a back seat as I focused on my family and career.

Then one day I heard about a marathon my company had been invited to join. It had been over 10 years since my last big race, but I put my name forward. “I’m surprised,” a colleague said. “You do realise it’s totally underground?” It turned out the race was in a Swedish zinc mine, 1,120 metres below sea level. That made it the world’s deepest marathon, and everyone who completed it would be a Guinness World Record holder.

Rather than putting me off, it made me more motivated. Stephanie was supportive, albeit bemused, when I explained my view wouldn’t be scenic woodlands, but grey rock walls.

In the end, 55 people from 18 countries signed up for the challenge at Garpenberg mine in October 2025. Some were experienced runners; others first-time marathoners. Many, like me, had never been inside a mine before. I had assumed it would be cold, but geothermal energy and the heat from mining machinery warmed the surroundings to about 24C.

The tunnels were pumped with fresh air from the surface to boost oxygen levels and were mostly unlit – hence the headlamps we were given with our safety helmets. We would also have to run in silence, as health and safety regulations didn’t allow headphones.

To prepare, I ran with my headlamp and helmet in the summer heat, getting some funny looks. When autumn closed in, I trained at night to practise running in the dark.

On the day of the marathon, I was nervous but excited. I’m not claustrophobic, but it was unnerving to know we were so far underground. I tried not to think about the 1,300 metres of solid rock over my head.

The mine was operational and I could hear the hum of machinery through the walls. As we were escorted to the starting point, I was fascinated to see vending machines and brightly lit offices. It was an entire underground world.

The tunnel was five metres wide and stretched for over a mile. To make up the distance of a full marathon, we would run to the end and back 11 times.

We had been warned about the heat, but I hadn’t expected the stifling 72% humidity, or how dark the tunnel would be. Beyond a few feet of light from the headlamp, it was utter blackness. But the adrenaline was pumping, so I began to run.

Usually, I blast Eminem to distract myself, so it felt strange to pound along in complete silence. But the biggest challenge was the monotony of those unending grey walls. The only relief came each time we passed back through the starting point, where people cheered us along.

At the start there was quite a party atmosphere; we ran in packs and I chatted with the others. But when we began to stretch out, I concentrated on putting one foot in front of the other, reminding myself this was a once-in-a-lifetime experience.

I kept pace with my colleague, Michael, just behind the frontrunner, a man named Mika. The first 20 miles weren’t too bad, but the last six were testing. Hours of running had churned up the floors. I could feel my face getting caked in dust.

Nearing the end, I realised Mika and Michael were slowing, while I still had a bit left in the tank. At their urging, I pulled ahead. I wasn’t even sure if I had counted the laps properly, but the cheering crowd confirmed that not only had I completed the marathon, but I had come first, with a time of three hours and 17 minutes.

I was amazed: I had never expected to win. The best feeling, though, was the camaraderie of that day. We were all there to congratulate the final runner when he crossed the line, then headed out for a meal and a pint, and toasted our record-breaking run. We all walked away as Guinness World Record holders. How many people can say that?

As told to Jacqui Paterson

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