The highest and oldest hut of all, it has just celebrated its centenary. By 4pm we had crossed the Bertol glacier, unroped, uncramponed and climbed the ladders up the rock-face to the hut.Bertol hut is the jewel of the Haute Route. On the valley floor, the Arolla glacier stretched out in black and white stripes of stone and snow from summers and winters of many centuries ago.All day as we climbed, the Bertol hut was visible above us teetering into the sky. We had a 1,300m climb to the Bertol hut which was perched like an eagle’s nest at 3,311m overlooking the greatest peaks of the Alps. Day five dawned pink and crisp as we strolled up the path towards the Dents de Bertol.

The reality was another vast plateau with the rest of the party disappearing specks over the distant edge.The sun came out on the fourth day as we sauntered round the grassy slopes of the Lac des Dix and down to the little Alpine village of Arolla. As I gasped for breath on reaching the col, my vision of cosy hut with smoke curling from its chimney and aroma of lamb stew seeping under its door, vanished. My nadir came at the top of the Prafleuri pass, having crossed what was known as Le Grand Desert From the pass, Neil had said, I’d be able to smell dinner. The Romans are said to have used these passes, and pilgrims and smugglers also regularly trekked along these routes.By the time we reached the Prafleuri hut, we had walked for 10 hours over rocks the size of buses.

Descending the Col de Chaux, we walked in the path of a receding glacier. The previous two days of rock and ice vanished into the stony fantasy above our heads.On the third day, the route from Verbier to the Prafleuri hut took us over three 3,000m passes through a moraine moonscape. We spent the afternoon in the balmy valley warmth, drinking beer by Champex lake. Then as we reached the La Breya chair-lift they vanished leaving brilliant blue. Sometimes they billowed up from underneath; at other times they engulfed us in a dripping fog. As we got lower, the snow turned to sleet forming glassy crystals on heather and moorland grasses.The traverse around the mountain to Champex was a gentle stroll with the clouds breaking up more and more. We set out through a blizzard, sliding down over the lateral moraine of Orny glacier.