Peak viewing: John Birt switches off from broadcasting and turns his energies to the physical challenge of a winter trek in the Himalayas

I set my alarm so that I would catch the dawn. I got up and waited in the dark, watching the cooks light the fire to make the tea and the porters extricate themselves from their blankets and put their hands to the flames for warmth. The trail dog was still slumbering. Surprised by my early rising, a woman porter scuttled away, embarrassed, from one of the Sherpa's tents.

The summit of Annapurna picked up the rays of the dawn first, glowing rose. The rest of the mountain was still pure white, lit only by moonlight. The sky in the east, opposite the mountain, lightened from deep turquoise to a pale primrose yellow, the clouds a muddy brown.

I looked back to Annapurna. The bare rocks now were a burnt sienna, the snows shaded pink and gold. A porter came over from the fire and admired the view with me. He had never spoken English in my hearing before. 'Beautiful mountain,' he said.

'Yes, beautiful mountain,' I replied. We were on the home leg of a 17-day trek which had begun in a village 12 hours' drive from Kathmandu. Our objective was to climb up and along the west ridge of Annapurna South to the sacred lake of Kaire Tal. It would be a circuitous route on minor trails across jagged mountain ranges to one of the world's highest peaks.

There were nine of us, all British. Six were in their twenties; two (one of them me) in their forties; and one - Tom, a retired head teacher - was 60. Most were fit and keen walkers, used to British footpaths. Tom looked an unlikely trekker in this severe landscape, but we soon learnt he had been a PE teacher and a champion runner in his youth.

We had a support party of 20 Nepalese - Sherpas, cooks and porters - to carry our tents and provisions and guide our way. The Sirdar - the leader of the trek - was Ang Domi Sherpa - a small, graceful man nearing 40 with kind eyes and a flashing smile. His calm dignity inspired immediate confidence. When not leading expeditions he was a farmer.

We were off the main trail, but - initially at least - we were not alone. Children would walk with us on their way to school. A group passed us carrying a dead body suspended between bamboo poles. We met families, some on journeys to see relatives 10 days' walk away. One man in a group carried a tiny old lady in a pannier on his back.

All goods traded in the villages are transported along the trail - some by colourfully adorned mule trains, the leader with a jangling bell dangling from his neck. But the bulk of trade is carried in baskets on porters' backs. We continually encountered small and slender figures, some past middle age, bent double with huge loads - five crates of beer on a single back was commonplace - walking deliberately, one short step at a time, up steep mountain sides. On downhill stretches they would break into a slow, shuffling trot. One day we caught up with an old man carrying four large sheets of corrugated iron wider than the narrow mountain ledge we were on. As we dawdled behind him we were reminded of the old music- hall joke with a ladder: if we asked to pass, would he turn to see who we were and in the process swipe us into the ravine below?

At mid-morning, wizened porters would stop and gather for a smoke and chatter along the way by open-fronted stone houses with brushed red earth floors - in effect, transport cafes where they would order tea and snacks cooked on clay wood stoves. The paths themselves were well maintained, with good stone steps on the steep inclines. In the forests there were stone huts for night shelter. On every hill, at regular intervals - even in wildernesses remote from villages - there were stone benches, like lay-bys, where porters could sit and rest and park their loads.

In the early days the villages were poor. There was no sanitation, and health care - from auxiliaries, not doctors - was days away. We were stopped twice on the trail to help with bad cuts. Life expectancy in Nepal is 54, and old people were a rare sight. The main sound in the villages was coughing. Everyone had runny noses and bad chests. Smoke-filled houses with open fires and without chimneys was one cause; and TB - we were told - was common.

Schools were rudimentary, with tiny classrooms containing rough- hewn benches, illuminated only by small, glassless windows. But for most of the day the children were out on the trail playing: the girls skipping and playing marbles; the boys playing chungi - with a football made of loosely meshed elastic bands. Babies were minded - and carried - by their elder sisters, generally only five or six years old themselves. In the evening the same young girls - not the boys - would fetch water for the household in bowls on their heads. Farming was biblical: water buffalo toiled on stepped terraces which swirled in neat patterns thousands of feet up the mountainsides.

After the first few days, the gradients grew sharper and the climbs longer. The landscape was on a scale beyond previous experience. We would climb for hours on end, reach a pass, then descend for hours. Calves and lungs protested on the way up, knees and tendons on the way down. We grew fitter and stronger.

We climbed above the villages and into the forest. Here there were only tiny paths and some of the porters immediately lost their way. An exchange of piercing whistles guided them to where we waited. They finally appeared, grumbling, and were subjected to prolonged teasing.

The vegetation in the forest varied enormously depending on the height of the hillside and its angle to the sun. Lower down there were banana trees; as we climbed, bamboo groves, then rhododendron woods; a little higher, tall trees encrusted with lichen and trailing long creepers; finally conifers.

In the lower forests in winter there are leopards and bears, but they are hidden by dense cover and rarely sighted. We saw nothing but monkeys and - on several occasions - glorious eagles soaring only feet away from us as we stopped to rest.

We reached the snowline at about 8,000ft. North-facing slopes, unwarmed by the sun, presented icy trails and new hazards. One morning, going downhill on a sheer gradient, I enjoyed a moment of solidarity with a passing mule. We both lost our footing together. We slid in parallel, she more gracefully, with all four hooves bunched together, pirouetting like a ballerina, perfectly poised and calm.

We spent a whole afternoon slowly descending a gorge on a path of hard snow that wound beside a series of waterfalls, each framed in icicles. A Sherpa cut steps before us with an ice axe on the most treacherous sections. I slipped, falling heavily on a young doctor in the group, cutting her hand. Twice porters slithered for long distances till they caught hold of boulders or trees, one losing his load into the ravine. The porters found any fall hilarious. News of incidents would be shouted up and down the gorge. One young porter - fed up with falling - finally took off his shoes and ran helter-skelter down the whole Cresta Run in his socks, a giant load on his back, singing loudly as he went, the rest of the party scattering out of his way.

Day began at dawn with the cooks delivering 'bed tea' to the tent. A few minutes later hot water would be brought for washing. Emerging from the tent to shave, a few days into the trek, I saw Annapurna for the first time, many days' walk away but already dominating the horizon with its distinctive inverted 'V' peak. Then we would pack - water, spare clothes and emergency materials in the knapsacks we carried ourselves; sleeping bags and everything else was in our kitbags for the porters to carry.

Our porters would gather about an hour after dawn. The kitbags would be assembled on a tarpaulin and distributed equitably to individual porters by Ang Domi. The porter who carried my kitbag - he was about 20 - carried three in all, as well as his own effects. I estimate his load - a struggle for me to lift on to his back - weighed about 70-80lb.

The porters were the cheeriest of our support groups, always quick with a smile and a wave on the trail. At rest stops, they were the first to start a snowball fight or to play practical jokes on one another. They were extended families of siblings and cousins. Five were women and carried lighter, but still substantial, loads. Two of the brothers looked alike and sang beautifully and in harmony except on the steepest climbs.

While the Sherpas dismantled and packed the tents, we would have breakfast - porridge, muesli, eggs. If we were near a village, children would come and watch us eat, sometimes barefoot and clutching skimpy, ragged shawls around them in the freezing morning air. We hit the trail around 8.15am, one Sherpa in the lead, one always in the rear, so everyone in the group could walk at his or her own pace.

We would stop around noon for lunch and a long break. The air would still be cold, but when the sun shone it was hot, so this was the one opportunity to wash and dry our clothes. It was also the only chance to wash ourselves properly. Whenever we stopped by a south-flowing stream, we would search out a pool by a waterfall, strip to bathing costumes, soap ourselves all over and rinse off in the shockingly cold water.

Lunchtime was a hive of activity. Sherpas and porters would combine in a slick operation, collecting wood and water and scrubbing pans. Soon the cooks would have a hot - and sometimes eccentric - lunch ready. One day I enjoyed a chapatti sandwich of tinned pilchards and boiled carrot.

In the afternoon, we would spend two or three hours on the trail before making camp for the evening. Tents were quickly pitched and bags unpacked before sunset. As I sorted out my tent one evening and dressed myself for the freezing night ahead, the women porters sang gentle songs together by their fire. Dinner was served around 6.30pm in a draughty mess tent. Afterwards, we played poker for rupees or read by kerosene lamp.

When we camped near a village, though, it was as if the circus had hit town. Our caravan of Sherpas and porters were experienced adventurers, men and women of the road, who had travelled and trekked all over Nepal. They knew how to enjoy themselves. After nightfall they would drink and make merry with the local fast set; flirt with the innkeeper's daughters; play cards noisily, slapping down each card hard on the ground with a spirited cry. One night it rained and the locals and our porters and Sherpas had a party in a schoolroom with raucous singing and frenzied dancing to the beat of a bongo drum.

They burst in on our group and dragged us out to dance, delighting in our clumsiness. We towered like giants over these tiny village people. They made me do a solo in the rain, squealing when I added some high kicking to the simple Nepali dance step they had taught me.

Towards 10,000ft the night temperature dropped well below freezing. Snuggled in a goose-down sleeping bag, however, wearing heavy-duty thermals on legs and body, walking socks, fleece jacket, scarf and balaclava, I was cosy and warm, and slept soundly.

One week into the trek we climbed through snow on to a ridge, turned a corner and saw the whole Annapurna range before us, rising to 26,500ft. We had come in January for the crystal-clear air of the Nepali winter. And this magnificent vista was our reward. It was our first clear sight of Machhapuchhare - a mountain from a comic strip, with a sharp, narrow knife of a peak with a curious, forked fish-tail top. Our spirits soared, all the burdens of our toil lifting in a single moment.

We dropped, in a difficult descent, to Ghorapani - a village on the main trail from Pokhara into Tibet. This is the 'tissue' trail favoured by young budget travellers - it owes its name to the trail of toilet paper they leave behind. We soon encountered a breezy New Zealand pair drinking beer. Later we met a young Englishwoman looking very sorry for herself. 'Nepal is too up-and-down,' she mourned, 'and not what I expected.'

We warmed ourselves by the wood stove in the first teahouse we came to. This was run by a gentle, sad-eyed, one-time Gurkha who had guarded the Queen in London and talked of his sorrow over the recent loss of the Gurkha battalions. This would have a major impact on the village's families, most of whom had sent their sons for generations to fight for Britain, he said. He offered us a shower in a wooden hut in his garden. Tepid water (heated by his stove) trickled from a waist-high tap and drained away through a rough hole in the corner on to the hillside below. It felt like luxury.

At sunset, Annapurna South loomed over us, the best part of 20,000ft from the valley floor below us to the summit above - an awesome, unyielding mass.

The villages closer to Annapurna were more prosperous. The farmhouses were substantial and clustered in larger villages. The women wore elaborate and colourful clothes and sat on their porches spinning and weaving, with large, sweet-faced dogs in attendance. A big-boned black dog joined us at the campfire one night and set off with us the next morning. We could not persuade him to return to the village. Ang Domi explained it was a trail dog which adopted passing groups. It was to stay with us to the end of our trek, always around when the food was - but undemanding and patient. He was happy to sleep outside, but the moment it rained - which it often did in the evening - he sought shelter in a tent. (On the last day, when we reached the metalled road, he watched us go, then set off back down the trail towards Annapurna.)

In the three days after leaving Ghorapani, we crossed the floor of the main valley on to the Annapurna massif; followed a long, sunless side valley leading towards the summit; gingerly crossed a fast-flowing river at the head of the valley on slippery, perilous stones; and made a long climb up to the main ridge which leads to the summit of Annapurna South itself. As the air thinned, we had to stop for breath more and more often. We became dehydrated and my skin became uncomfortably dry. I lost my appetite. But on the third day we hauled ourselves up on to the main ridge to our new reward: a renewed sight of the summit of Annapurna South - now much closer at the end of the ridge above us - and a glorious view directly on to neighbouring Dhaulgiri, higher than Annapurna, and the mountain I was to become most fond of.

For many years Dhaulgiri was thought to be - and indeed still looks as if it is - the highest mountain in the world. The Dhaulgiri range comprises many jagged peaks, their summits forming a long, sweeping curve. In the middle is Dhaulgiri itself - a monolith, a square slab of a fortress in blunt counterpoint to its sharp sister peaks. This would be our view for the next two days.

We set off on a side ridge running north from, and at right angles to, the main ridge. We immediately encountered deep snow. After two or three miles, we made camp in a position looking directly on to the vast, bare, sheer, west face of Annapurna South, with its giant glacier. From the camp we could now see clearly the whole length of the ridge leading to the summit and could understand why this frightening jumble of pinnacles had never been climbed.

Our camp was on snow, on the spine of the ridge, exposed to the elements. We had planned to make camp the following day higher up the mountain; but it looked as if the heavy snow would be hard going for the porters. Ang Domi proposed a recce before nightfall. We set off, wearing waterproofs over our warmest clothes, with light snow falling, along the side of the ridge. The virgin snow was often up to the top of our legs and it was soon evident that it would be impassable for the porters with their heavy loads. We turned back, disappointed.

The porters were huddled by the campfire when we returned. One had his bare feet in the fire, flames licking his hardened soles. They were visibly relieved to hear they would not have to walk on. Ang Domi proposed that the trekkers should leave at dawn the next day and try to cover in one day the distance we had planned to walk in two and a half: we would try to reach - and return from - the sacred lake, Kaire Tal, trapped by a wall of rock below the summit at nearly 16,000ft. It was a daunting prospect, but everyone in the group was ready to try. At sunset, the condensation on our tents suddenly froze a brilliant white. When I unzipped the fly-sheet, thousands of tiny ice crystals showered upon me. My sleeping bag had a thin sheen of ice.

That night we all retired early, but were soon awoken by a fierce, moaning wind. I lay awake, fearful of being blown off the ridge. It was an odd storm: without warning, the wind would stop and there would be silence. Then, just as suddenly, it would blast into us again. Around four, there was a furious flapping, as if my fly-sheet were blowing away. I rushed out to find the toilet and mess tents half down. For the first time on the trek, I slept poorly. An hour before dawn I reached for my water bottle, to find it frozen solid. The day's walk was an intimidating prospect. I resolved to pack for severe emergencies - down jacket, thermals, warm clothing. We were up before dawn. The group was quiet and nervous.

Ang Domi set a fast pace uphill to the main ridge. Soon we were in the snowfields. He took long, bold steps, only occasionally stopping and exploring for drifts with his stick. Wading through the snow was exhausting; I felt borne down by my heavy pack and I struggled to keep up. I hoped my lungs and limbs would soon start to work. After an hour I summoned up some resolve, shed the unnecessary equipment I had packed, and shoved it under a boulder to be picked up on the return leg. I felt no better. I was the heaviest of the group by far and the footholes made by others would regularly collapse under my weight: I tumbled into the snow over and over again. My hands are normally warm, so I was not wearing gloves; but soon they were blue with cold. (Later I realised that they had been cold-burnt in the freezing snow.) My distress was spotted: one of the group made me stop and retrieve my fleece gloves from my backpack. My hands soon warmed. I plodded on. Slowly my strength returned.

By mid-morning I had recovered and was walking well again, pulling myself quickly to my feet after every tumble. But Tom, the retired head teacher (and his Sherpa), had fallen way behind. He had been wearing many layers of clothing, but at the last stop he had said he had not been able to warm up. One foot was freezing in his 35-year-old boots. He said he had never been colder. For four and half hours we struggled along the side of the ridge. Any sudden effort brought a reminder of the altitude and a sharp gasp for breath. Twice the snow beneath my feet collapsed completely and wedged me between boulders. The youngest of the Sherpas scampered nimbly across the snow and hauled me out.

Sometimes our boots would break through the snow to the sheer ice on the slope below and slide our legs from beneath us. The slope we were traversing led to a precipice that dropped thousands of feet to the valley. Sometimes we walked close to the edge, but I was concentrating too hard on the next step to worry. One of the Sherpas did fall, prompting squeals of delight from his comrades; but he dug in his elbows and knees and soon came to a halt.

We stopped climbing at noon to allow an hour's rest and sufficient time to return to camp before dark. We were glad to stop. We were now over 13,000ft, but only half- way on the day's over-hopeful leg to Kaire Tal. Still, we consoled ourselves, no one had been any higher for many weeks. We presumed Tom had returned to camp with the back-marking Sherpa. We drank in the view of Dhaulgiri and the other peaks, dazzled and thrilled by the beauty of it all. I spied tiny dots in the distance: it was Tom and his Sherpa. They grew closer and finally reached us towards the end of lunch, making one slow but dogged step at a time. We applauded Tom's arrival.

It took seven days to come down from the mountain and complete our journey to Pokhara. For three days we walked through mountains, so shrouded in mist and cloud that we could not see them. Until the night that I set my alarm and rose in the early hours to see the sun rise on Annapurna, the beautiful mountain.

John Birt travelled with Exodus Expeditions, 9 Weir Road, London SW12 OLT (081-675 5550). The cost of the holiday was about pounds 1,800, including out-of-pocket expenses, but excluding kit.

Fitness: All treks are graded. Most would be suitable for anyone used to long-distance walking holidays in Britain. But it is best to arrive in Nepal fit and with your weight down.

Time to go: In the winter months the weather is cold; the snowline starts at around 7,000ft and deep snow from about 12,000ft will prevent you climbing as high as you can in summer. But the winter air is crystal clear and the views magnificent. The spring brings flowers and warmth, but the risk of hazier visibility.

Kit: The trekking company supplies the tent and a list of what to take. Specialist clothing can be hired in Kathmandu. But the prudent will take, for the cold evenings, their own heavy thermals, fleece jacket and trousers and a duvet jacket. A five-season goose-down sleeping bag will keep you warm at night, and Gore-tex trousers and jacket will keep you dry.

(Photograph omitted)