Tenerife is all about fish 'n' chips, Essex girls and timeshares, right? Wrong. Michael Williams explores the other side of this holiday island

It's a game I bet many of you have played before. You know the kind of thing. You've both done a bit of exotic travelling in your time. So the conversation runs: "Where shall we go?" And then the bidding starts. How about a bit of meditation on the slopes of Mount Fuji? Or the slow train over the Andes? And what about that hot new spa - some kind of converted cowshed in Azerbaijan. All Philippe Starck, I'm told.

Trouble was, we'd been liberated from our jobs for a mere four days. True, a heroic granny was offering to look after our four-year-old. But options even for the two of us in the middle of winter were starting to look decidedly limited. Cyprus? Too middle-aged and no guaranteed warmth. Cape Town? Too far. Sharm el-Sheikh? Wasn't that where the Blairs went?

"So what's wrong with the Canaries?" (Equable temperatures, guaranteed sunshine, mellow seas and three-and-a-half hours from Gatwick.) "Are you serious? What about all those Essex girls, time-share touts and Ambre Solaire? It's the last place on earth I'd go. Might as well take a break in Basildon."

"Have you been there?"

"No. Have you?"

"Er, no."

So here we are on the tarmac of Reina Sofia airport on the south coast of Tenerife. The air is filled with the scent of jasmine and that sensuous, piney smell so redolent of evenings in southern Europe, the terminal is delightfully uncrowded, and the scheduled flight out of freezing slushy London was spot on time. But I remain grumpily out of synch when I find that I can't get our rather beat-up, hired Corsa into reverse, and the man at the desk warns us against my meticulously charted route over the mountains

Our destination is Garachico, in the green and, we're told, unspoilt north-west of the island. The squiggly mountain road is apparently too dangerous at night, so we head out on to the motorway that encircles the island. Tenerife may be a backwater of provincial Spain and 100km off the coast of Africa, but the trip along the T1 makes the anti-clockwise section of the M25 seem enticing. Jockeying through the four-lane section past the tower blocks of Santa Cruz and the north coast is like rush hour on the Euston Road.

Two hours and three-quarters of the island later, we swing off down a darkened road to the coast, where we can just spot the lights of Garachico twinkling by the sea. We park the car by rocking it back and forth into the kerb, too tired to sort out the reverse gear. It seems oddly quiet, even though it's only 10pm with just the mutter of the sea audible at the end of the street. I think of Dylan Thomas's "starless and bible-black" as we unload our bags.

The entrance to the Hotel San Roque is little more than a hole in an ochre-washed wall, but step inside and you can see why many reckon this to be the best hotel in the Canaries. An elegant, galleried 18th-century merchant's house, set intimately around two courtyards, it is reminiscent of the grand villas of Old Havana. We get the measure of the place when we're shown to the "junior suite", cleverly converted from two old rooms overlooking the pool. Careful not to fall into the giant Jacuzzi in the corner, we decide not to be tempted by the hi-fi, the DVD player - and hit town. After all, isn't this what the English are supposed to do here? And we all know that no self-respecting Spaniard goes to a restaurant before 10pm.

But as we stride out, the streets are still deserted, with only a few cats padding around in the moonlight. Are we early, or are we late? The question is soon answered as we settle down for last orders in one of the few cafés still open along the back streets. An aromatic, but very local, salt cod stew, a bottle of the volcanic Tenerife wine and the unhurried welcome of the young owners set the tone for our holiday.

Daybreak reveals all. Here in the shadow of Mount Teide, Spain's highest peak, is a charming town of shady squares, convents, narrow streets and whitewashed houses, adorned with the carved balconies of the old Canaries. There is no whiff of fish and chips, just the tang of the Atlantic and the scent of orange groves - and instead of the clack of white stilettos, the more familiar sound is the clip-clop of the priests across the square.

So how come we've stumbled across this timeless patch of old Spain in 2006? Partly because Garachico is a town that has always been left behind. Founded four years after Columbus's famous voyage, it was the island's premier port in the 16th and 17th centuries. Then Mount Teide erupted, washing the harbour out to sea. Garachico has slumbered ever since, somehow staying out of the guidebooks and off the beaten track. There is no beach, but the legacy of the volcano has left a labyrinth of black rock pools in which you can swim.

We spend four days pottering. The temperature hovers in the seventies, but Tenerife is an island of microclimates, and when the panza de burro ("donkey's belly") hangs over Garachico we drive out west over snaky roads and stunning scenery to the lonely Teno peninsula, where the sun blazes from a blue sky and we squint past the lighthouse in the hope of spotting one of the 26 species of whales and dolphins that pass by here regularly.

Another day we lunch on fried sea bream in an ancient café, step a few yards back to our hotel and spend the afternoon playing Scrabble by the pool, rounded off with a session in the Jacuzzi andCalendar Girls in our room.

Can Garachico's unspoilt atmosphere last, I ask Dominique Carayon, the San Roque's French owner one evening. He and his wife have restored the hotel from a ruin, retaining its historic charm, but filling it with modern art. He tells me he's fought with the municipality to keep the area unspoilt. But the motorway will come, and he, nearly 60, likes the idea of retirement.

We never did get to the summit of Mount Teide, the one thing we had vowed to do on leaving London, partly because of the mist, but mainly because of the Carayon family's hospitality and sybaritic life in the San Roque. But we had a rare treat as our plane took off for home. There it was in the sunshine, its crater poking through the clouds just beneath us. Come back again, it seemed to beckon. And we will.

The author travelled as a guest of British Airways (0870-850 9850; ba.com). It offers return flights from London and Manchester to Tenerife from £99 and £129. Double rooms at Hotel San Roque (00 34 922 133 435; www.hotelsanroque.com) start at €183 (£130) per room per night b&b