Gaping Gill: Mix of terror and euphoria during my adventure at Yorkshire's deepest underground cavern

But the return haul to the surface was different. I now knew just how high I was going, and dreaded the tight confines of that black hole above the vast main chamber.

A thought flitted through my mind that I was placing a lot of faith in very thin strands of steel cable when my progress seemed to falter, the cables began to creak as if stretching to their limit, and the chair shuddered a few times.

As it turned out, this was a sign that the winch was slowing my ascent, ready to bring me back into daylight, but palpitations shot through my heart and unleashed a tsunami of adrenaline.

All of which instantly subsided when the sun hit my face, I was released from the chair and felt the euphoria of finally ticking off an experience that’d long been on my bucket list.

For Gaping Gill is one of those Yorkshire experiences that sooner or later you have to do, the opposite of standing on the summit of Whernside, Yorkshire’s highest point.

Over the years I had often passed Gaping Gill’s huge surface crater on the path up to Ingleborough from the village of Clapham. It was always deserted, fellow walkers keeping a respectful distance from the abyss into which tumbled Fell Beck.

But on the day of my descent it was crowded, with tents creating an almost carnival atmosphere. Bradford Pothole Club’s annual winch meet draws people from far and wide - I found myself talking to people from Surrey and Lincolnshire - but for all those who got there early enough to guarantee a place on the chair there were as many who came too late.

The cavern is on a bigger scale than photographs suggest, and a 3D model of its dimensions suggest a size roughly similar to the interior of York Minster.

Floodlights illuminated just part of it so my torch was needed to explore the far corners, its beam revealing a constant aerosol of fine droplets from the waterfall.

The floor is surprisingly flat, and covered in slippery stones like a pebble beach when the tide is going out.

A cluster of chocolate-coloured stalactites, each around 26ft long, hangs near the waterfall, and there are several underground routes into the wider 12-mile-long Gaping Gill system that has been explored by potholers.

But these were cordoned off, and for visitors like me the steel chair was the only way out.