It is all Mick Jagger's fault. Twenty-six years and two months ago I spent the summer, with a university friend, gardening for an elderly English woman - an ageing courtesan as it turned out - in the South of France.

She lived in a beautiful but ramshackle villa, just outside Biot, a classical Provencal, hill-top village, only a mile or two inland from the concrete and palm tree excesses of the Cote d'Azur. In those days, according to my memory, you only had to move a couple of miles from the coast to enter a different world: a world straight from the pages of Marcel Pagnol; a world of crumbling villages and tiny vineyards and cunning Provencal peasants (as yet unpatronised by Peter Mayle).

I left the village in August 1971 to hitch-hike home and have never been back. Until this week.

I feared the worst. A few years after we were there, Mick Jagger had bought a home in Biot. The village, I was warned, had become irretrievably fashionable.

Driving up the steep, spiralling road to Biot, I was encouraged at first. The old place did not seem to have changed beyond repair (although I didn't recall the multi-story car-parks). Finding the villa where I had worked outside the village - the Mas des Lievres (Hare Grange) - was another story.

I recalled unpaved tracks and vineyards and lavender fields and cicadas and dragon-flies. Instead, there were entire estates of mock-Provencal farmhouses; there were chain-link security fences and hungry-looking dogs; there were bulldozers and miniature tower-cranes, helping to prop up more villas.

The Californication of the South of France is now intense. In the last quarter of a century, the Cote d'Azur has become a great, linear city from Cannes to Menton, indistinguishable in its shabbier stages from parts of Florida or California. There is even talk in Paris of recognising this de facto reality and creating a new urban, political entity for the Cote d'Azur: a kind of gallic Los Angeles. Taking off from Nice airport, you see that the suburbs of the coastal megalopolis of over 1 million people now spread 10 miles or more into the Alpine foothills.

My ex-employer, I knew, had died several years ago. She was from British racing stock, and had been established in the villa in her relative youth by a Middle Eastern potentate (whose name was the first in the visitors' book). Somewhat down on her luck by 1971, she clung to the fringes of the old British tax-exiled aristocracy of the South of France. Graham Greene, who then lived down the hill in Antibes, was also in the visitors' book. Our employer promised that "Graham" would come to one of her parties. He never did. Instead we - long-haired and leftist as the times demanded - would mingle in grim delight with stiff-backed, retired admirals who insisted that Edward Heath was a Communist. Why? Because he had not abolished income tax yet.

Something of this world still exists. But it has largely been displaced by a different expatriate community on the Cote d'Azur, rich and energetic, rather than rich and idle: everyone from Ringo Starr to, the most recent arrivals, the Spice Girls. Mr Jagger has long gone.

After several false starts, I gave up and put the hire car into a multi- story car-park and set out on foot. In desperation, I turned into a smart road in what looked like a suburban estate. After a half mile, the mountains up on the Italian border to the north-east began to assume a familiar pattern. Between two new villas and a miniature crane, there was a neat, concrete road and a sign: "Mas des Lievres".

This was it. This road was the track besides which Mike and I had grumblingly worked for several days, scooping a ditch out of the rocky soil. This was the garden which our employer had filled with lawns and hedges and rosebeds, as if she still lived in Suffolk. Just watering it had occupied several hours every morning and evening.

Now the lawn had reverted to scrub; the hedges and roses were gone. A formidable security gate blocked the way. The farm next door, where the farmer's 17-year-old daughter watered the geraniums in her bikini, had become another look-alike villa. An unfriendly face stared out at me from an upstairs window.

I turned and walked back to Biot, feeling old. The last time I had come down this road, I was 21 and about to embark on the great adventure of hitch-hiking to Cherbourg.

I stopped in a bar in Biot for a consoling lunch. This was, surely, the bar in which I had spent the evening before my departure. My companion that night was another fellow student, who had arrived to take over from me. He was a startlingly intelligent, and aggressively homosexual young man whom I barely knew. (He is now a celebrated novelist and biographer.)

Bored with my tales of life at the villa, he began to chat up a good- looking village boy in French even more appalling than mine. He proudly announced, after a few minutes, that his new friend had agreed to walk with him to see the sea. I thought this mildly odd since the sea was two miles away. I said nothing and went home. Five minutes after I got back, so did he. His friend had taken him, he explained irritably, not to see la mer (the sea) but to see la mairie (the town hall).

The past is another country.