There was no warning. I had hurtled downhill off the rough roof of Thunacar Knott and as I approached Martcrag Moor, the ground, previously solid, became liquid.

Wooomph!

I began to disappear. Calves gone. Knees gone. Thighs gone. Waist gone. Gasping, a thousand thoughts a moment, body flailing forward, legs scrambling for traction. Swimming, wriggling, groping.

Wooomph! The bog released me.

When was the last time I had inelegantly wallowed waist-deep in a bog, I mused as I resumed my hurtle on an indistinct and sodden track, now to the outflow of Angle Tarn. That was it. Hell Down South, November 2010. I waded through the ironically-named Bog of Doom, a 100-metre or so long trench of brown water. Since a bog – to be pedantic – is an area of ground too soft to support significant weight, the Bog of Doom is not even a bog. The process, therefore, of passing through the Bog of Doom is as contrived as Peter Andre tombstone piledriving Kim Kardashian at WrestleMania XXX.

There lies the magic of fell running: a sport that does not need gimmick or invention, the very antithesis of contrived. The sport is a rebel with a cause – a cause of dismissing the average, the norm, the constriction of health and safety.

A rush and a surge, and a field of 400 competitors in the annual Langdale Horseshoe fell race in the Lake District are running, spilling east on a track, before turning sharply up an ever-climbing path to Stickle Tarn. The steepest sections are walked, with the runners’ gait  becoming long and determined, the shoulders hunched. I look up, then glance down. An unending snake of colourful runners. The navy and green of Ambleside, the purple of Borrowdale, the turquoise of Helm Hill, the brown of Dark Peak. It is utterly beautiful.

The rules of the race are simple. Start at Langdale. Visit six checkpoints among the Central and Southern Fells. Finish at Langdale. How the runner gets from checkpoint to checkpoint is their business, for the route is gloriously unmarked.

To call myself a fell runner would be an insult to other fell runners. While I may be the 1837th member of the Bob Graham Club, having scaled 42 Lakeland peaks, covering 66 miles and ascending 28,000ft in the process, in under 24 hours, when racing at Pendle in April, I – a Birmingham-born London-dweller – had never felt more foreign anywhere in the UK.

My forays to the Lake District are fleeting. Fleeting and precious. My running world is south London and predominately the streets of Croydon, Streatham and Tooting: roads, pavements, paths around parks, tartan track. A world away from the rough and ready moors and mountains.

Yet the first half of the Langdale Horseshoe suited the southerner: the ground, apart from Martcrag Moor, was firm; there were trods and generous paths; the gradients were moderate. At the Esk Hause checkpoint – a glamorous term for a man with a piece of paper – the racing route turned sharply south-east on a route that even the notes on the map described as ‘dreadful but right’. A real fell runner would scoff at my indifference as I cursed and blundered my way along the ‘dreadful’ route. A path, yes, but a path on a wicked camber, over sodden ground, rarely flat and littered with rocks.

Bowfell – England’s sixth highest mountain and the zenith of our pursuits – beckoned, its head lost in mist. As I descended, the mist lifted, revealing the rolling madness of the exquisitely-named Crinkle Crags. While others skirted the ridge, I stayed high, running solo; for a few minutes this was my mountain alone. On Crinkle Crags lurks the Bad Step, a 10ft rock scramble that is easier to go up than down. ‘Leap onto a walker or climb down with care,’ the map advises. I plunged down inelegantly, before a glorious, on-the-limits-of-control rush downhill to the lower slopes of Pike of Blisco, on top of which was the final checkpoint. I resume my climbing stoop and I am soon there, blinking in the wind. It is all downhill from here.

We – a man in a Bingley vest and I – had been running downhill for two or three minutes, taking turns to lead, hurdling grass tussocks, veering past rock outcrops, squelching through bog.

‘Do you know the way?’ I asked.

‘No.’

A pause.

‘Do you?’

‘No.’

We blundered on. You are are wearing a Bingley vest. You are from the north. You are virtually local. How can you not know the way?

‘The map?’ I shouted back. He shook his head. So did I.

We blundered on. Maps remained folded in our respective bags. My earlier comments on the map’s contents are merely in hindsight.

Above a crag, we paused. We looked around, scoured the mountainside. In a race of almost 400, there was only Bingley and I, as well as two fools who had blindly followed our tracks. We had not found a short cut.

It should have been all downhill from Pike of Blisco. We climbed, contoured and sweated over long grass, before the race route – marked by a drawn-out line of plummeting humans – reappeared. Now it really was down, down, down, and sprinting along the road to the finish, I stole a glance right at Bowfell and Crinkle Crags, intoxicated by the knowledge that I was up there only minutes ago.

The next day, before catching a train back to London, four of us – all members of the Bob Graham Club – ran into the Howgills from Sedbergh, chasing each other to the top of Calf Top. The train home was shockingly fast. In what seemed like moments, I had gone from running in the empty Howgills, gazing across grey skies and green hills, to riding a swaying, cramped and angry (and a hundred other awful adjectives) bus from Brixton to Streatham. I could have wept. I was back in a contrived world.

A version of this article also appears on the SportPursuit website.

@MuirJonny