TGO's guide to the GR20, the toughest waymarked trail in the world. By Cameron McNeish

THIS particular Grande Randonnee, the French equivalent of our "official" long distance trails, boasts a near-mythical status amongst mountain walking enthusiasts.

It is often described as Europe's toughest trek, and even as a two-week long Cuillin Ridge, and one wonders how much of that mythology has been created, or talked up, by those thousands who start the route every year, but find it beyond them?

It's been claimed that about half of the annual 17,000 hikers who attempt the GR20 drop out along the way, many of them on the dank and austere rim of the steeply forbidding Cirque de la Solitude, or on the very first day out of Calenzana, a day that involved a 1500m/5000ft climb, in hot temperatures, and with a heavy pack.

The route begins in the mountain village of Calenzana, near the coastal resort of Calvi in the north-west of Corsica. It ends at Conca, in the south-east of the island. The common assumption is that the route simply climbs to a high mountain ridge and then follows it south for a hundred miles but the reality is considerably more complex.

For a start the island of Corsica is not made up of one single mountain range but a number of ranges, each thrusting its steep-sided and forested flanks across the breadth of the island. This, in effect, means that the long-distance walker faces a corrugated route of considerable ups and downs with a total ascent of some 12,500m/41,000feet. Mount Everest is only 29,028ft!

The rugged nature of the trail can be established by the fact that it took Chris Townsend and I thirteen days to walk the route, the length of which is anything between a hundred and a hundred and twenty miles in length - it's very difficult to get an accurate mileage on such unremittingly rough terrain. However, while an average distance of 10 miles a day is not very impressive in itself, most days involves a climb of Munro-height on invariably incredibly rough trails, often with a fair amount of hands-on scrambling involved too.

Those are the cold, maybe even chilling, statistics of the route, but around those hard facts you have to weave the beauty, grandeur, atmosphere and sheer incongruity of the route.

Conceived in the 1970's by the alpinist Michel Fabrikant, the GR20 is obviously a mountaineer's route, but a route that, in reality, actually poses very few technical difficulties. While it certainly follows high and exposed ridges, few are as awkward as the Cuillin or the ridges of Arran.

Some sections, like the steep sided slabs in the Spasimata Gorge or the descent into the Cirque de la Solitude, are potentially dangerous, but in situ chains and ladders take the sting of the technical difficulties. Throughout the route there is a wonderful sense of mountain wilderness, but a system of mountain refuges, or huts, allows you to sleep in a soft bed and have a hot meal and a beer every night.

The GR20 then is not then, ostensibly, as tough as its reputation would have us believe, although both Chris and I reckoned it was the toughest "waymarked" trail either of us had experienced, not so much a sheep in lion's clothing as a wolf in lion's clothing!

The reality is that the vast majority of hikers we met on the trail were fairly inexperienced - you could tell that by the vast loads they carried and the way they carried those loads. If you are a reasonably fit and regular hillwalker and can cope with carrying a loaded pack over hills for up to six or seven hours a day then you should have no real difficulty on the GR20, indeed, it could well one of the great mountain experiences of your life!

Day 1: Calenzana to Refuge D'Ortu di u Piobbu This is claimed to be the hardest day on the entire route and we would concur with that, the difficulties exacerbated by the fact that we had got out of bed at 3am that morning to catch a 6am flight from Edinburgh to Bastia.

We were very fortunate to get a lift from the airport at Bastia to the start of the route but the downside of that was we began hiking, with full loads, at 1pm in the heat of the day, and it was very, very hot - well over 35C.

It was certainly a gruelling introduction to Corsican backpacking, but not without its delights. Starting on an ancient mule track we climbed up through a delightful mix of maquis, chestnuts and Laricio pines with wonderful views of the nearby coast.

Forty-five minutes from the star of the trail we filled up at the last water source until we reached the refuge, some six or seven hours away. How much does four litres of water weight?

It was early evening when two weary backpackers climbed out of the forest on the start of the ridge at the Bocca a u Saltu pass. I think we were too tired to appreciate the views and we were well aware we still had to climb to an even higher pass, the Bocca a u Bazzichellu, through an area with some fairly exposed scrambling.

We were tempted to camp wild and try and make up time the next day but unfortunately the Parc Natural Regional de Corse forbids wild camping, although you are permitted to camp at the designated camping areas beside the refuges.

The views from the higher pass of the shapely outlines of Monte Cinto and Paglia Orba did a lot to rejuvenate us, as did our first sighting of the Refuge d'Ortu di u Piobbu, even though we still had a high level traverse of the cirque above the headwaters of the Melaghia River before we reached it.

Day 2: Refuge d'Ortu di u Piobbu to Refuge de Carozzu I suffered badly from cramps throughout the night, a sure sign I had lost too much salt and was probably severely dehydrated. Despite that we looked forward to our first full day on the trail, a short 5-mile day, but one that involved two and a half thousand feet of ascent and three and a half thousand feet of descent!

We began with a pleasant climb through the forest and around a broad shoulder before descending to the Mandriaccia river where we took on the day's supply of water. A long climb followed, up an open valley with red rock towers and spires on either side.

Bare rock stairways and boulder fields took us higher towards an obvious gap in the ridge above - the Bocca Piccaia at 1950m/6400ft and our first real sighting of the kind of terrain that was in store for the next two weeks.

We weren't disappointed. The views down into the steeply rugged Cirque de Bonifatu were stupendous - sheer walls of rock leading to a serrated skyline and peak upon peak drifting off to the south towards the slouch of Paglia Orba.

We traversed the rim of the Cirque, squeezing through gaps in the rock, clambering up and down slabs and crossed another col, the Bocca d'Avortoli before starting the long descent to the Carozzu valley and the Refuge where we would camp. Cold beers slipped down with a sizzle..

Day 3: Refuge de Carozzu to Haut Asco Another apparently short, but tough, day - less than 4 miles, but with an ascent of Munro-height and a descent of not much less! The highlight of the day was negotiating a long series of steeply sloping slabs high above the Spasimata river. These Spasimata Slabs are protected by chains and handrails and are in a wonderful setting far below the red ramparts of Punta di Spasimata.

We met some hikers who had obviously decided this was the end of the line for them but I thoroughly enjoyed the exposure and the mountain setting. Chris wasn't quite so happy on the slabs and I put this down to the fact he was still wearing sandals. Was he to become the first backpacker to hike the GR20 in its entirety in such footwear?

Beyond the slabs the trail climbed steeply to a north-facing gully full of rock rubble. This led to another gap in the ridge below the peak of Muvrella and more rock scrambling to another col, the Bocca a I Stagni. From here a long and knee-crunching descent took us down to the ski station, restaurant and refuge at Haut Asco.

Day 4: Haut Asco to Bergeries de Ballone There was a useful little backpackers' store at Haut Asco and we loaded up with cheese, chorizo-style sausage and bread and enough pasta to last us several more nights. We ate in the restaurant at the ski station and the conversation with other hikers was full of nervous expectation of the next day - the dreaded Cirque de la Solitude.

An easy trail climbs up towards the tiny lakes at Altore just below the Cirque de la Solitude but long before we reached the rim of the cirque we felt the silence. Cold and clammy, it spilled over the edge and touched us as we climbed the steep snow slopes that lingered above the Altore valley.

A gaggle of fellow hikers loitered on the edge, curiously silent, all gazing down at the depths that fell from their feet. Then we saw it ourselves - a huge, cleaving space, a breath-taking gap in the face of the earth from which the silence rose, a silence so profound that the ugly chaos of rock, scree and snow appeared to be enveloped in it.

Before lingering fears could tempt us back from the brink a harsh sound broke through the silence - the rattling of chains on rock. Below us a trio of backpackers were carefully lowering themselves down the first of a series of stepped granite walls by means of a carefully positioned chain whose clanking sounds reverberated around the steep walls and spires of the cirque.

Even further away, another small group of hikers were carefully negotiating a route through steep slopes of scree and ice. Beyond them others were preparing for the climb up to the far rim of the cirque, the Bocca Minuta. We certainly weren't alone in the so-called Cirque de la Solitude.

The two-hundred metre descent into the steeply concave cirque is reckoned to be the crux section of the GR20. As Chris and I finally began to ease ourselves down the granite grooves, walls and slabs we started to appreciate the formidable landscape. Surrounded by spiralling granite towers and spires and entertained by yellow-beaked Alpine choughs we hauled ourselves up the chains on the far side, danced across steeply inclined slabs and negotiated the ladders that climbed the steepest sections of the route.

Three hours later we were sipping cold beers on the sunny verandah of the Bergerie de Ballone, wondering if the highlight of the route now lay behind us.

Incidentally, the seriousness of this section can be established by the fact that Chris changed his sandals for a pair of trail shoes

Day 5: Bergeries de Ballone to Hotel Castel di Vergio After the rigours of the last four days this one promised to be slightly easier - a long and gentle forest descent eased into a steeper and rocky climb to the Bocca di Foggiale.

We decided to bypass the Refuge de Ciottulu and simply drop down from the pass to a delightfully green valley that could easily have been in the Lake District. We ate lunch by some sparkling pools in the river before continuing our descent past the ruined Bergeries de Tola, to the Bergerie de Radule, with its herds of goats. A pleasant woodland walk took us to the D84 road and the hotel at the ski station of Castell di Vergio.

The camping area here was in an enclosed field to protect camper's belongings from the foraging of feral pigs. Curiously, Chris was awakened in the wee, small hours by something hauling his beloved sandals out under the flysheet. By the time he got out of the sleeping bag one of his sandals was gone, never to be seen again. Despite searching everywhere for it, he never found it. Was it a pig, a cat, a dog? We'll never know

Day 6: Hotel Castel di Vergio to Refuge de Manganu A 10-mile day today, with about 2300ft of climbing, and most of it fairly easy. A long walk through a beech forest started the day in good style, although Chris was already missing his sandals. A straightforward climb took us to the windy Bocca San Pedru where a long and delightful ridge walk traversed the Serra San Tomaghiu before cutting across the southern slopes of Capu a u Tozzu to the Bocca a Reta.

From the pass the trail looked delightful - an easy descent led to a broad and fertile looking valley that cradled the biggest lake we had encountered so far, the Lac de Nino. From there it was a long walk down slopes of juniper and yellow spiny broom to the Bergeries de Vaccaghja where we bought some more cheese before a gentle climb took us to the Refuge de Manganu.

Day 7: Refuge de Manganu to Refuge de l'Onda We kicked off with a long and gradual climb that rose to a series of stepped meadows, the sites of ancient glacial lakes. These meadows fell down from the high and rocky Breche de Capitellu like a string of green rosary beads and the Breche itself, the gap in the cliff-like rocks that towered above us, was protected by a large snow wreath.

Fortunately we could clamber up a gully at the side of the snow towards the narrow fissure in the cliffs and as we squeezed ourselves through the dank and rocky portals of the Breche the view that suddenly lay before us exploded in on our senses. It was as though the whole world had suddenly opened up in a new and vividly colourful dimension.

Day after day we had arrived at steep-sided mountain passes, each crossing gently suggesting a little victory in itself, each viewpoint offering a different perspective on these rugged Corsican mountains, each high-point reflecting our inexorable progress down the mountain ridges of the island, but this high pass contained all the elements of the extraordinary.

It was only later that I realised this was the highest point on the whole route - 2225m/7300ft above the Mediterranean. Probably because of the elevation the mountain ranges of the rest of our route unfolded, ridge upon ridge, shadow upon shadow, away to the haze of the south, but it was the closer view that contained the real drama.

Below our feet smooth granite slabs dropped away into a pair of high and awesome mountain corries, each cradling a deep blue glacial lake. Like emeralds in the face of the earth they glinted and glistened in the morning sun, deep-set in their crater-like hollows.

From our high eyrie above the lakes we could just discern people by the shores, tiny dots the size of insects negotiating the boulders and slabs. They would have climbed there from a car park at the head of the Restonica valley, and even that "tourist" route would have involved climbing metal ladders, hauling up on a chain and a lot of hands-on scrambling. There are few easy routes on the mountains of Corsica.

The rest of the day was a dream and we felt so good we elected to bypass the Refuge de Petra Piana, the normal stopover for this section, and continue to the next refuge at l'Onda, a reasonable enough day of 20km/12 miles and 1370m/4500 feet of climbing.

Day 8: Refuge de L'Onda to Vizzavona This day should have felt like an anticlimax but such was the sustained climb up to the Punta Muratello, with fabulous views back towards the fin-backed ridge of Serra de Tenda and the double peaks of Punta di I Pinzi Corbini, that it proved more strenuous that the map suggested.

From the narrow gap of the Punta Muratello we traversed great, granite slabs above the headwaters of the Agnone river. Further down, we enjoyed the shade of easy forest footpaths all the way down to the tiny railway village of Vizzavona, effectively the half-way point of the route and the best hot showers of the route.

Day 9: Vizzavona to Bocca di Verdi After stocking-up on Camping Gaz, buying more food, enjoying a hot shower and an excellent meal in the Restaurant-Bar l'Altagna we slept like babies in the woods close to the village, an area now designated as Vizzavona's official camping area.

Well fortified, we could attempt the biggest day so far - almost 31km/19 miles with 1320m/4330ft of climbing. It sounds worse than it was. Good mule paths climbed through the forest to the pass, the bare and windblown Bocca Palmenti, from where a gentle traverse followed the west flank of the Fium Orbu Valley.

A short but steep climb led to the ski station at E'Capanelle where there is a refuge and a gite d'etape. We stopped long enough to slide down a cold drink and an ice cream before heading off towards the Bocca de Verdi where we bumped into Paddy Dillon, author of the Cicerone Guide to Corsica.

Day 10: Bocca di Verdi to Refuge d'Usciolu Paddy was re-working his guidebook and we chatted late into the night. He was heading north, to Monte Renosu - we were going south, up to the Refuge de Prati and then along a seemingly never-ending ridge where the path switched from one side of the ridge to another often with gully scrambles leading to toothed notches in the ridge.

Sadly we didn't see much of the views - this was our only bad weather day of the trip and we were swathed in cloud and mist for much of the time. When the cloud did eventually clear we found ourselves close to the spot where Connie Roos, the guidebook author, was tragically struck by lightning a few years ago. It was a poignant moment.

Day 11: Refuge d'Usciolu to Refuge d'Asinau The Refuge d'Usciolu had the most amazing little store where you could even buy hiking boots! We stocked up for the remainder of the trip before tackling another long ridge, the rocky Arete a Monda, which led down to the extraordinarily beautiful Plateau du Cuscione.

The wilderness camper in us longed to pitch our tents here beside one of the swirling rivers with views of Monte Incudine before us, but instead it was an ascent of the 2134m/7001ft peak that filled our afternoon, with fantastic views back towards the distant Paglia Orba and the ferociously serrated outline of the Aiguilles de Bavella before us. The descent to the refuge felt like the steepest of the trip, a long and very rough descent that played havoc with our knees.

Day 12: Refuge d'Asinau to Refuge d'I Paliri A long and easy descent down the Asinau valley took us to the Col de Bavella, a windy mish-mash of car parks, hotels and carbon emissions. With too many cars for our liking we ate a hasty lunch, and high-tailed it back to the woods for a long and delightful walk to the equally delightful Refuge d' I Paliri.

This hut, and its camping areas, had an other-worldly atmosphere, like Alice's Wonderland and come morning we were sorry to leave. We were experiencing those bitter-sweet moments that accompany the last hours of any long and memorable hiking trip.

Day 13: Refuge d' I Paliri to Conca The last day of the GR20 was not without drama - magnificent views of the spires, pinnacles and crags of the d'Urnuccio Aiguilles accompany you almost to the coast and now, as we descended in more dramatic terms, we could almost smell the brine of the sea. A long traverse around a final cirque took us to a prominent gap in a rocky wall, the Bocca d'Usciolu, and from there is was a steep drop down forest tracks to Conca, and the wonderful Gite d'Etape La Tonnelle offering hot showers, good food, beer, a camping area and a taxi service down to the resort of Porto Vecchio.

Our abiding memories of walking the GR20 would principally be of a high and sustained mountain walking route, in which there are few "easy" days to allow the body to recover from the previous day's exertions.

But having said that, the delectable blend of mountain and sea views, the long days of good weather, the scent of laricio pines in the hot sun, the delight of peeling your socks off and plunging your feet into a mountain stream, the camaraderie amongst mountain walkers of all nationalities and perhaps above all else the marvellous sensation of simply being amongst glorious mountains for almost two whole weeks, put all the harshness and physical difficulties of the route into context. It was, undoubtedly, one of the finest routes either of us had ever hiked.

Information

How to Get There,/p> We flew with BA from Edinburgh to Bastia, in north-east Corsica and were fortunate in that we managed to arrange a lift to the trailhead at Calenzana. The airport at Calvi is much closer to Calenzana and there is a bus service connecting the two, although the timetable appears to be pretty erratic. You'll get up-to-date information from Les Beaux Voyages; 04 95 65 15 02 Calvi is connected to Bastia by a year-round train service.

When to Go,/p> Chris and I hiked the route during the last week in June and the first week in July. Even then, outside the French holidays, the route was busy and some nights the refuges were pretty full. Late July and August are very, very busy and tents are packed together on the camping areas like sardines in a can. May and early June can be difficult because of late lying snow but September can be a wonderful month. TGO's designer, Robyn Frew, hiked the trail last September and said it was relatively quiet, but still with generally good weather.

Accommodation

Our excellent hotel accommodation at the end of the trip, in Porto Vecchio, was arranged for us by Corsican Places, Cutter House, 1560 Parkway Solent Business park, Fareham. Hampshire PO 15 7AG: 0845 330 2345; www.corsica.co.uk The same company also arranged our flights to and from Edinburgh to Bastia. Corsican Places also have a property in Calenzana, at the beginning of the route. En route we camped at the designated areas around the mountain refuges. A number of the refuges sold cooked meals, most stocked basic supplies. We regularly bought cheese and sausage from bergeries on the trail. The refuges all offered basic hut accommodation.

Money

Cash is king on the GR20. You won't find any ATM's, neither on the trail or in any of the small villages you pass through. Chris and both carried about £200 in euros and that was easily enough to cover camp fees ( 4 per night) three good restaurant meals, beers most nights and enough food to last us the trip.

Onward Transport from Conca

The Gite d'Etape in Conca offers a good taxi service to either Sainte Lucie de Poirto Vecchio or Porto Vecchio itself. From there Rapid Bleau (04 95 70 10 36) runs two daily services up the coast to Bastia via Solenzara and Aleria. Alternatively, Eurocorse Voyage's buses run from Porto Vecchio to Ajaccio; 04 95 70 13 83. For more travel information contact the Tourist Office; 04 95 70 09 58

Guidebooks

GR20 Corsica, The High Level Route, by Paddy Dillon (Cicerone Press) Trekking Corsica, by David Abram (Trailblazer)

Fuel

It's worth noting that camping stove fuel can be a problem on the route. The only fuel that appears to be available on the island is Camping Gaz, although the screw-in CV 470 cartridges appear to be as available as the more traditional Camping Gaz cartridges. We both used an MSR Superfly stove, a multi-mount backpacking stove that works with a variety of self-sealing canisters, including the Camping Gaz range. Most of the refuges have cooking areas for campers, usually with a gas ring, but we found them uncomfortably slow to use.

www.corsica.co.uk

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