Khardung La has its head in the clouds and its height in doubt. Is this really the world's highest road pass? The sign at the top reads '18,380 feet' (5,602 metres) but some say that refers to the old mule track higher up. Measurements abound, with different results, but those who make it to the top stand firm: barring a few dirt tracks in neighbouring countries, this Himalayan pass, in northern India's Jammu and Kashmir state, is the highest drivable road in the world.
Once a permit has been secured in the town of Leh, the drive begins with long leisurely zig-zags back and forth across the barren slopes. Far below, the Indus river is just a scratch on the landscape, the oasis of Leh dwindles away and we are confronted with the mountain desert of Ladakh. The South Pullu checkpoint is the last sign of human life, except for the odd biker, hungry for a challenge and truckers, eking out a living. After that, there is no turning back.
In this sensitive border area, the road from Leh to the Shyok and Nubra valleys is maintained by the Indian army; there are no crash barriers but enough tarmac to call it a road and enough potholes to keep drivers on their toes. It's wide enough for a truck (although we spot the remains of two over the edge) and traffic is one way: up from Leh in the morning and down after lunch. Permission to bend the rules is sometimes granted so it's best to remain vigilant.
It takes two hours to cover the 37 kilometres from Leh to 'K-Top' but it can take a lot more if a truck breaks down or it snows. Such delays provide an opportunity to gaze at the precipitous drops, the boulders balancing overhead and a wilderness that even goats refuse to venture into. There isn't a tree in sight, just loose stones and shrivelled up lichen. 'Always keep a cheerful attitude,' is the official advice and, taking that on board, when a truck decked out in tinsel begins to honk, it feels like a party.
Glaciers glint, peaks rise, jagged as a knife's edge, and the first prayer flags flutter to wish you luck. Soon there's a whole forest of them and you can barely see the long-awaited hut serving tea and noodles. It's an inviting sight but you can't come this far without climbing to the shrine on the hillock.
We are told to avoid running or moving too fast. 'You have gained 7,000 feet [2,100 metres],' we're told. That's a lot in two hours.