I was three weeks too late for the romeria, the annual midnight trek to the top of Mulhacen, the highest peak in mainland Spain. During the night of 5 August each year, Andalucian pilgrims climb the 11,420ft mountain in honour of the Virgin of the Snows. These noctural ascents have at least one advantage - they avoid 'red runs', or long periods of walking in direct sunshine.

For me, ability to endure red runs (Mulhacen can only be walked without snow-gear in summer) would decide whether or not I'd be joining Abdul Muley Hassan, the penultimate Moorish king of Granada, buried on the heights of the mountain that bears his name.

Treks usually begin from Trevelez. Some 40 miles by road from Granada, this is Spain's highest village, with steep streets perching on a hillside 4,700ft up the Sierra Nevada range. Our trek, though, began lower down and several miles further south, at Orgiva. Here I joined eight fellow trekkers, at the house of Carole Donovan, our guide, who has lived in the region for the past 20 years.

The first evening meal was so quiet that I wondered whether it was the start of a group therapy session, rather than a trekking holiday. Who would confess their inadequacies first? We all had our reasons for trekking in the Sierra Nevada, but no one was letting on. I had an altitude problem: I'd only ever walked in the Lake District before, nothing on this scale. My first inkling that I might be a little out of my league came during some pre-dinner map reading. 'I presume these contours are accurate?' Jane, a cheerful researcher from London, asked Carole.

The next morning, after catching a bus to Soportujar, we took to the sierras along a river valley. Following caminos, narrow mule tracks, we climbed our way up scented hillsides, through a perfume of wild mint and thyme. Great expanses of forest and wild flowers are sustained by melting snows from the peaks flowing through channels built by the Moors centuries ago.

It was about 20 minutes before I found myself trailing behind my companions. Until I caught up with them at the lunch stop my only companions were yellow and turquoise bee-eaters. Ahead of me, my fellow trekkers were taking it all in their stride, among them an eye surgeon, an anaesthetist, a computer programmer and a librarian. Wordless, with heads bent, they moved with quiet determination like silent pilgrims. Penitential garb, however, was replaced by garish fleece jackets, backpacks and hiking boots.

Only when you are at the back do you realise the advantages of being at the front on trekking holidays: longer breaks when the group stops, and someone behind you to notice if anything falls out of your backpack. During the week-long trek the only time I was at the front was when sitting beside Alessandro, our driver on the three-hour journey from Malaga airport to Orgiva.

At times it seemed as if my fellow trekkers only wanted to scale Mulhacen to get over some terrible personal tragedies. During the first afternoon's climb the link between trekking and psychology was hinted at when Richard, the anaesthetist, offered me some fatherly advice: 'Never look back,' he said. 'Only forward.'

On the second night we stayed in Carole's isolated cortijo (farmhouse), in the Soportujar forest, amid hundreds of king- size pine cones. Plumbing was non-existent, so I sluiced myself in the freezing flow of a nearby river. Later, to pre-empt any complaints about my snoring, I tied a plastic water bottle to my backside to prevent me from sleeping on my back.

We left at sunrise the next morning. Ascending the high ridge of the Sierra Nevada, we soon spotted the long curving horns of the cabra montes, the shy wild mountain goat of the Alpujarras, the southern slopes of the high sierras. We managed to walk within 100ft of the animal before it ran off.

A third of the way up, Sue, the librarian, decided to turn back. Andrew, an enviously superfit 29-year-old, offered to escort her to the road where she could catch a lift back to Orgiva. Four hours later, as the rest of us scaled the upper slopes, vultures circling overhead, I wished I'd joined her. But I struggled on, reminding myself that after Switzerland, Spain is the most mountainous country in Europe. I'd also begun to confuse Exodus, the trekking agency that had organised our trip, with a famous voluntary euthansia organisation. 'No, that's Exit,' one of my companions reassured me.

Temperatures had dropped and the varied flora of the lower slopes gave way to surreal, monochrome hillsides. The strange, moonscape-like quality made it easy to forget how close we were to the welcoming Moorish towns of the Alpujarran valleys below.

When we eventually reached our dormitory at the Refugio Felix Mendes at 8pm, I headed straight for the nearest bottom bunk. I'd had enough of climbing and walking for one day.

I felt vindicated during that evening's meal when two of the most experienced trekkers admitted it had been one of the hardest day's walking of their lives. At last we were one, united in the insane expressions of exhaustion that only trekkers have after a tough trip.

Keeping a safe distance from the sheer drop of Mulhacen's north-west face early the next morning, we followed an exposed ridge to the summit. We had been promised panoramas at the top; views stretching as far as Morocco and over to the central plains of Spain. Unfortunately, the mist even denied us a glimpse of Granada and the Alhambra just a few miles north.

From the top of Mulhacen we took an eastern descent via the Siete Lagunas (Seven Lakes) down to Trevelez, famous for its local air-cured hams, dried by exposure to alpine winds.

'Air-cured ham?' I asked during a break. 'What was wrong with it the first place?' Such an awful gag was met with richly deserved groans from my fellow trekkers. For a while I had few friends in high places.

Now, a descent of Mulhacen would be easier than going up, right? Wrong. Going down was harder; less time to appreciate the scenery and more concentration required. Take your eyes off your next foothold and you might lose your balance.

The next day, time off in Trevelez coincided with market day. While others embarked on a five-hour trek of the 7,700ft Penabou nearby, I relished my freedom. Taking a stroll through Trevelez's cobbled streets, I was admiring the flower-filled baconies when a senora tending to her plants unwittingly watered me. She waved an apology before rushing inside.

In Trevelez's main square you soon realise that there can never be a Spanish branch of the Noise Abatement Society. Like many towns in southern Spain, there seems to be some unofficial rule that transistor radios must blast to distortion. Only when a Civil Guard truck passes is there any attempt to lower the volume.

Until we reached Trevelez, contact with local people had been minimal. With washing-up rotas, packed lunches, a group leader and shared dormitories on some nights, trekking holidays can feel like school trips. Throughout the trek I expected to hear our leader, Carole, call out, 'There's somebody talking now]'

The following day our descent from Trevelez took us through spectacular gorges. Berber refugees from Seville first settled here in the 12th century, and later the area was the Moors' last stronghold in Spain before they were driven out by Ferdinand and Isabella. After the fall of Granada some Moorish families remained in the villages to teach their complex irrigation systems to Christian peasant colonies from Galicia and Asturias.

En route to Pitres, we travelled through Pampaneira, Bubion and Capileira, the charming white villages of the Poqueira Ravine, all with flat-roofed houses clinging to steep mountainsides. Snow-capped mountains competed with the brilliance of the whitewashed villages below.

After checking into the Fonda Sierra Nevada in Pitres' spacious main square we sipped early evening drinks at a bar opposite a white parish church. On the next table several old men were playing dominoes, slapping down pieces and commenting on their moves in raspy voices. 'What do the women do when their men play dominoes?' wondered Jean, one of my energetic companions.

Next year, their games of dominoes face competition from the World Ski Championships, due to be held in the Sierra Nevada. Unlike trekkers, skiers will get a lift to the peaks.


Flights: Iberia (071-830 0011) has scheduled flights from Heathrow and Gatwick to Malaga for pounds 150 return until 7 July. After that, charters from agencies such as The Flight Company (081-977 9455) cost around pounds 169.

Walks: Mulhacen is accessible to walkers from end-June to end-September. Max Wooldridge's trip was organised by Exodus Expeditions, 9 Weir Road, London SW12 0LT (081-675 5550). A Mulhacen Ascent, 2-9 July, costs pounds 340 (including flights).

Further information: Spanish Tourist Office, 57 St James's Street, London SW1A 1LD (071-499 0901).

(Photographs and map omitted)