Travel: High times on a hard road: Crossing the mountains of Corsica on foot, Tim Salmon experienced the heights of pain and pleasure, and made friends along the way

I needed a rest. I was the one who was struggling today. We had been climbing for five hours and my last reserves of will-power were all but exhausted. We sank into the metre-high alder scrub that provided some protection from the cold wind that raked the slope beneath us. We were close to around 2,000 metres.

'Punaise]' said Michel (it's the French equivalent of 'gorblimey'), 'it's freezing.' He had goose-pimples all up his legs and arms. He was always cold, always aching, always railing against the world, yet he made us laugh with his sour humour.

There were four of us now: a Breton, a Corsican, an Alsatian and an Englishman. We had each started alone but teamed up gradually in the course of the march.

As we lay, spent, in the scrub, we heard the clank of water bottles and the scrape of boots. Two athletic French girls lowered themselves round a chaotic pile of rocks above us.

'Nearly there,' said Jose the Corsican, facetiously. 'Only five hours and flat as a pancake all the way.'

'And the same to you,' said one of the girls.

'What's the refuge like in Vizzavona?'

'Accueil bizarre - but worth it.'

'We're going the wrong way,' said Jose, looking longingly at their departing backs.

In 15 minutes we were on the ridge. Cloud was closing over the heights, obscuring the crags and pinnacles of the Monte d'Oro to our left. Immediately below began a steep descent into the valley of the Agnone stream.

Reinvigorated by laughter and relief at the end of the climb, we descended fast for an hour, dancing from rock to rock, absorbing the shock with taut thighs, until first Jose and then yours truly lost our footing on wet rock and skidded - luckily - to a soft landing on our rucksacks.

After that we went more cautiously down into beautiful woods of pine and beech, their leaves already beginning to carpet the path with autumn colour, while the stream beside us slid effortlessly over glacier- smooth slabs from pool to pool in a series of falls known as Les Cascades des Anglais.

It took four hours and more to reach Vizzavona. We arrived in dogged silence, no energy left for wisecracking. There were no hanging gardens, none of the sherbet-sipping houris we had fantasised about: just three dilapidated hotels, a couple of houses and a tiny railway station.

But the Bar Refuge de la Gare more than lived up to its reputation. The floors were bare, damp had blown the plaster from the walls, cobwebs festooned the discoloured 19th- century mirrors, and the dewlapped patronne watched over all, especially the money, like a stern-eyed Cerberus.

But the shower was hot, a fire burned in the grate, and Marie-Jo, the friendly, generous cook-waitress served an ample and delicious meal: sufficient luxury after eight gruelling days in the mountains.

Vizzavona is the halfway point on the GR20, the path that crosses the mountains of Corsica from Calenzana in the north-west to Conca in the south-east. It is not a route for first-timers and should be approached with caution in uncertain weather. They say it is the toughest in Europe and my body told me they are probably right.

Though the path is well marked and the way easy enough to find, each day brings cruelly long and steep ascents followed by precipitous descents. These would be ferocious enough with just a sandwich in your pocket and a sweater tied round the waist, but the killing factor is weight. You do not need a tent or much in the way of clothing - in summer, at least - for there are manned refuge huts every five to six hours. The problem is food. The refuges do not serve meals and there are few places to buy provisions along the way, so you have to carry a minimum of three to four days' supply at a time.

If you are not fit you will suffer torments. And even if you are, my strongest recommendation is to keep the weight to an absolute minimum, which means no such extras as cameras and binoculars, only one change of clothes, and a diet of dehydrated food and muesli, to be supplemented by taking maximum advantage of the ski stations or sheepfold restaurants and stores which you encounter roughly every three days. I carried about 16 kilos, including a bivouac bag which allowed me to sleep out and enjoy the moonlight. But I could have done with 6kg fewer.

Despite the pain, the rewards are great. For days on end you inhabit a world of rock and air, of granite cliffs and narrow saw-toothed ridges, where a toiling ascent in the morning shade leads to a sudden breche and a plunging view to a tiny glacial lake or a sunlit traverse round the head of a yawning chasm. Intoxicated by the grandeur, exhilarated by the physical achievement, you lose all sense of time and your mind is purged of ordinary cares and preoccupations.

For me, the absolute highlights were crossing the Cirque de la Solitude and the night I spent in the Bergerie de Tolla. The Cirque is an awesome pit of tumbled rock and steep slabs some 250m deep. At first sight, fear loosens the knees; there appears to be no way through. Yet, while it is certainly no place for novices or those with a fear of heights, it is perfectly manageable in dry weather, and once your nerve steadies it becomes an exciting challenge.

Tolla, on the other hand, is balm to the soul. It lies in a bracken-filled clearing among the pines, and is one of the few remaining active bergeries. I was asked to help with the goats. The goatherd and I wrestled four of them, butting and slithering, down the path in the gathering darkness to where he had left his Jeep. As a reward for my labours I was invited to share the evening meal. We sat with his wife and a hired man in their candlelit hut, lulled by the gushing of the spring outside, swapping tales of shepherding round the Mediterranean, for she, it turned out, was a Parisienne child of the Sixties who had hitch-hiked through Greece and Turkey in her youth.

I spent the night under a pine tree watching the constellations wheel across the vault of sky above my head.

(Photograph and map omitted)