Deep issues: Martin Robson’s fight for his life underwater

More than 200 metres beneath the surface of a mysterious lake in Russia, I reached the bottom and knew I was in a place that no other human being had ever experienced before.

Wrapped in the icebox grip of the water, I saw the fine layer of silt and rock disappear beyond the beam of my torch and did exactly what I had planned to do on making it to the bottom of the lake: I went off exploring.

In the depths of Blue Lake, in Kabardino-Balkaria, southern Russia, I was a British adventurer in an alien world. I was there in search of a submerged cave never before seen by the human eye. I lived for such places and such moments. But I never expected that this might leave me fighting to save my life.

I am one of the world’s leading instructors in deep diving and cave diving. In January 2012, I joined a multinational expedition exploring Blue Lake. Located in the Caucasus Mountains, the lake has confounded many people. Every day, millions of litres of water pour from it, but the lake level never drops. Yet there is no in flow of water at the surface. That is why some people believe in the existence of an underwater cave.

As a former Royal Marine Commando, I had spent most of my adult life exploring submerged caves, snaking through narrow passageways and floating through vast cathedral-like chambers with stalactites hanging like chandeliers.

For me, there’s nothing like it. Imagine the most amazing geological structures carved into the most otherworldly shapes by the water. They surround you – up, down and sideways – and you are weightless in water so gin-clear it hurts your eyes, and all you want to do is see what’s around the corner.

Alone in the utter darkness of the lake’s waters, I was eager to see what lay ahead as my dive computer registered the depth, 209 metres – the equivalent of 47 double-decker buses stacked one on top of the other. At this depth, time is short. Twenty-five minutes into the dive and I reluctantly head for the surface. Ahead of me lay the long process of ascending.

In physical terms, 200 metres does not sound far, but deep divers who venture into extreme depths know they must practice extreme caution on their way up. Underwater, the helium and nitrogen in a diver’s breathing gas dissolves into the tissues of the body. Those gases need to be flushed safely from your system on ascent in order to avoid decompression sickness, commonly known as “the bends”.

To do this, I had a carefully calculated plan to pause at specific depths for set periods of time. In total, the ascent would take 10 hours. I had done this hundreds of times before and everything was going according to plan as I made my way to the surface. But even if I did everything right, there was still a remote chance that something could go wrong.

Six hours into the dive, it did. I was just 23 metres from the surface, exactly where I had planned to be, when I was ambushed. Bubbles exploded in my spine and took my legs. It was like being shot in the back.

Instantly, I was paralysed from the waist down.

Faced with such a situation, an unnerved man might bolt upwards. My legs dangling beneath me, I had other ideas –a high-stakes gamble not for the faint-hearted.

The surface is no friend in such a situation. My only hope was to descend back into the deep, to crush the bubbles in my spine and buy me some time to work out how to get out.

My fate looked grim, but this action managed to restore limited movement to my legs. I stayed underwater for hours, the cold water slowly nipping away at my body until I could bear it no more. Within minutes of surfacing, the paralysis returned.

I was taken to hospital, but I needed a miracle. My Russian friends found it – in the hands of an elderly doctor from Moscow and a dramatic mercy mission organised at the highest levels of the Russian government.

Dr Gennady Sokolov was Russia’s finest mind on decompression sickness. He knew first-hand what it was like to get decompression sickness after he suffered a serious attack following a deep dive in the 1960s.

In the dead of night, he helped arrange for me to be transported to a treatment facility hundreds of miles away in Sochi. There, he locked his new patient inside a re-compression chamber and initially pressurised me to the equivalent of 100 metres. Using a treatment method he had specifically designed for such injuries, Dr Sokolov hoped it would be enough to save me and my legs.

During nine harrowing days under pressure, I battled the horrors inside my body and pushed myself to my physical limit. As I felt the feeling return to my legs only to subside again, I was driven by one sole objective, telling myself: “I’m going to walk out of this chamber on my own two feet”.

Between the Devil and the Deep: One Man’s Battle to Beat the Bends by Mark Cowan and Martin Robson, is out now (Unbound, £25).