Chris Horsley’s work as an expedition photographer has taken him across Indonesia and Papua New Guinea, where he spent time living with remote tribes to capture how old traditions and modern lifestyles are being fused together. More recently, he travelled down the Blue Nile in East Africa to document the potentially devastating impact the construction of a new dam could have on the tribespeople whose land lies on the river’s banks.

Horsley’s real passion, though, is volcanoes – and at the age of just 26, he has established himself as one of the UK’s foremost volcano climbing experts. In his work for Active Volcano Expeditions he has led tours into the interiors of some of the most active volcanoes on the planet; he’s also slept inside the craters of Mount Marum and Mount Benbow on the island of Vanuatu (the first person ever to do so) and survived potentially deadly rock fall on more than one occasion.

For obvious reasons, volcanoes remain some of the least visited places on Earth, making Horsley something of a pioneer in the world of exploration. So how does it feel to descend into such a deadly environment – to go where none have gone before?

What’s going through your mind when you’re descending into an active volcano?
‘I always keep an eye out on team members and conditions, but my biggest focus is looking up at my ropes and making sure there are no loose rocks that could potentially dislodge. The scariest thing about volcano climbing is not the lava below you; it's the rocks up above. You can imagine how much loose material is held in by ash and unstable substance, so the biggest cause of injury would be rockfall. You have to put 100% trust in the equipment and on the first couple of descents down you do something called descaling, which is removing all the loose material from the wall on the way down.’

‘We're pretty much the only company operating this on a commercial level, so we are pioneering a lot of equipment and finding what suits volcanoes best, because it's so abrasive – so harsh and corrosive – that standard climbing gear doesn't hold up to what we need, so we're designing our own equipment. A lot of standard equipment is aluminium-based and the corrosive atmosphere of a volcano is highly acidic; it eats through aluminium in a matter of weeks.’

Have you ever had any near misses?
‘I was putting a zipline up inside the volcano, pretty close to the lava lake, and the rockside was dislodged. It came down on top of me from about seven metres above. Luckily my climbing partner gave me the rock sign, so I managed to swing my legs out the way to avoid most of it, but a basketball-sized rock did smash into my upper thigh. It was a pretty hairy moment, but I was back to work the next week.’

What’s it like to sleep inside an active volcano?
‘I've slept inside both Marum crater and Benbow crater, which was the first time anyone had ever done so inside either of those volcanoes. If you imagine setting up a tent in a glowing red caldera where there is no escape, you're looking up at a starry sky and you've got this boiling red magma pot right next to you. You can feel the vibrations going through the floor from the magma chamber and the constant aroma of sulfuric acid wafting through the tent overnight can become quite unpleasant. One fantastic thing about volcanoes, though, is that there is really nice underfloor heating, so you never really get cold!’

Is there one volcano that’s top of your bucket list?
‘It's Mount Erebus in Antarctica, because the challenge of that place is phenomenal. It's at a greater altitude than other volcanoes we operate on, but also the temperature up there is insanely cold and not only do you have the harshness of an erupting mountain in Antarctica, but the eruption it causes is called the “Erebus heartbeat”, which is a massive globular eruption that happens every two days.’

Find out more about Chris Horsley and his work for Active Volcano Expeditions at Christopherhorsley.com. Follow him @chrishorsley.

Words: Isaac Williams