Take a walk on the wild side

Virginia Woolf thought that Cassis in Provence was paradise on earth. Ray Kershaw took the footpath overlooking the dizzying Calanques, or creeks, to nearby Marseille

From the lip of the track the mountain plunged 1,200 feet to water truly bluer than the sea on our map. We were so high that the surf was just a whisper. Up here there was breeze, but even that was hot. Though less than 10 miles from the hubbub of Marseille, the coast was wild.

From the lip of the track the mountain plunged 1,200 feet to water truly bluer than the sea on our map. We were so high that the surf was just a whisper. Up here there was breeze, but even that was hot. Though less than 10 miles from the hubbub of Marseille, the coast was wild.

The ridge fell inland to a wilderness loud with cicadas. Through this terrain, the Grande Randonnée 98 – one of France's long-distance tracks – tortuously links Cassis and Marseille. The footpath is contoured like a switchback – but it was the scenery that robbed us of our breath.

My wife had needed tearing away from Cassis's siren-like charms. Voted by Virginia Woolf as paradise on earth, cognoscenti still rate it the most beautiful resort between Italy and Spain. For most of its history, beginning with the Greeks, the only access was by sea. Squeezed into its bay by Europe's highest cliffs, geography has made it impossible to blight.

Although today urbanely spruce – even boasting a casino – it remains at heart a fishing village that has grown organically. Boules click all day on the harbour-side pitch. Its animated market has the down-to-earth flavour of deepest Provence. Dufy and Matisse would still find inspiration from its prettiness and light. Surrounded by almond and olive and fig trees, its 13 small vineyards make a rare golden wine that renders Provençals lyrical. "It shines diamond-clear," wrote the poet Mistral. "Smells of the rosemary and heather that cover our hills."

Each sunset, Cassis mounts an extravaganza. The escarpment of the towering Cap Canaille glows like molten gold. As the incandescence fades, floodlights discover the 13th-century castle and leave it floating in the night sky. Sipping pastis across the twinkling harbour, my wife interpreted the alchemy as a spell to make us stay, but to me it was an omen for our walk. Crowning all Cassis's glories are the Calanques.

The Calanques (the name means "steep" and comes from the Provençal calenco) are fjord-like inlets which penetrate the rock for up to a mile. Canyon walls hide tiny, pine-fringed beaches. Divers adore their astonishing limpidity; rock athletes dangle between blue water and blue sky. Ferrying tourists to view the first three is Cassis's biggest industry, but the GR98 track, rugged and fragrant and even here little used, flaunts them like pearls. Next morning, we followed the red and white flashes painted on trees, in a sun-suffused mist, the inlets from above had an ethereal look. By our first real climb from the spectacular Calanque d'en Vau, limit of the tourist boats, crowded Cassis already felt remote. Ahead was seriously wild country, no water, no supplies – just sea, scrublands, silence and sun.

Walking the crest of the 1,000ft-high Devenson cliff felt rather like flying. Far below, birds wheeled dizzyingly. Petrels and gulls shared the vertical airspace with falcons and owls and Bonnelli eagles. The inland crags were like dazzling ramparts holding back the modern world.

Successive forest fires have taken the trees but the labyrinth of valleys was dense with flowering broom. All wildlife is protected but the final Hermann's tortoise was probably cremated in the last blaze. This Dantesque notoriety – proving undeserved – is perhaps what keeps the track, despite its beauty, so unfrequented.

From the Col de la Candelle, the track's highest point, the view of the coast from long invisible Cassis to still invisible Marseille was essentially primeval. With no sign of habitation, the cliff dwellers here three millennia earlier would have recognised their home. Deep in the mountain they had left a marvellous legacy.

In 1991, diver Henri Cosquer found a submarine passage to a cavern adorned with palaeolithic paintings. Seals and fish – rare in cave art – show that their creators were people of the sea. Their bizarre situation and perfect preservation got Cosquer branded a hoaxer until testing proved them to be 30,000 years old. Few have seen them – the entrance now is sealed – but somehow knowing they were there made the ancient arid landscape feel less austere.

Of the Calanques before Marseille the next three are the most exquisite. Accessible only by boat or on foot, two have fishing hamlets that seem to be from another age. One thousand feet below, the tiny beach of the Calanque de Surgiton felt as untrodden as Robinson Crusoe's. Then via a metal ladder, a scramble round a headland, was the Calanque de Morgiou: a finger of water dotted with boats, a huddle of cottages, and the ramshackle Nautic Bar where we rehydrated with Perriers. The equally pretty Calanque de Sormiou is a mere map inch farther, but by here you may be aching – literally – to break the journey overnight.

The walk is 20 miles – 12 hard hours plus rests. We took a day, but two would be better. The untamed coast has no accommodation. Camping is prohibited. But Sormiou is not as far-flung as it looks. Marseille's suburbs have crept up behind the hill. From calanque to calanque the track hovered horizontally midway down cliffs through woods full of birdsong, flowers and lizards, butterflies and bees. As untouched by man as Eden, the scent of hot resin competed with honeysuckle, lavender and thyme.

With still no sign of habitation, the track finally snaked to an interminable beach. Then yet another weary climb and suddenly below us, hiding in its own calanque, was the village of Collonges, the road head from Marseille with cafés, restaurants, bars. Buses from Collonges run every 15 minutes. Urban life called.

A bath and some beers later, by Marseille's old harbour we felt we deserved bouillabaisse. Cassis felt far away but, completing the circle, we drank, of course, Cassis white wine.

Getting there: you can fly non-stop to Marseille from Gatwick on British Airways (0845 77 333 77, www.ba.com), and from Stansted on Buzz (0870 240 7070, www.buzzaway.com). Fares are likely to be in the range £100-£300 this summer. By rail, you need to book two weeks in advance for the fare of £115 return on Eurostar (08705 186 186, www.eurostar.com) via Lille, Paris or (on summer Saturdays) Avignon Ville.

More information: French Travel Centre (09068 244 123, 60p per minute; www.franceguide.com)