‘Well,’ says Younghusband, ‘to the Tsar, then’, and turning his head away slightly he touches the flask to his lips and lowers it without swallowing. Nicolas finds himself offended by the half-heartedness of the Englishman’s attempt at civility.

Younghusband dismounts. He is wiry, big-boned, a nervous red setter of a man, with a young dog’s restlessness and anxious curiosity. He gestures at some bulky objects on one of Notovitch’s ponies.

‘You map-making? That a theodolite?’

‘No, Captain Younghusband. It’s photographic equipment. My editors tell me that our readers have a vast appetite for images of exotic locations. We journalists are slaves to the public taste. And as for you, what is the purpose of your expedition?’

‘I’m on Her Majesty’s business,’ says the Englishman. Then, aware how curt he sounds, he elaborates a little. ‘I’m adventuring. Bit of a passion of mine. I started in Peking.’

‘You’ve come from China?’ The distances involved are so huge that it’s impossible not to be impressed. Younghusband concedes he has with a false show of modesty. ‘Then the spirit of Drake and Raleigh is not dead,’ Nicolas suggests.

‘No, and never shall be, I hope,’ says the Englishman, with the pomposity that Nicolas has come to recognise as that nation’s birthright. He graciously accedes to the wish with a nod.

One of Nicolas’s Pashtun guides chooses this pause to break into the conversation. He’s wondering how long they expect to stay here.

Nicolas asks him if there’s water nearby. The guide indicates a thorn tree half a mile away on the valley floor. Nicolas tells him to head there and make camp.

‘You speak the lingo?’ says Younghusband in surprise.

‘My Pashto is no more than workable,’ insists Nicolas, ‘my Balti poor, and my Ladakhi practically non-existent. I’ve told my man to make camp by that spring. I would be honoured if you would be my guest tonight.’

‘What spring? The charts don’t show a spring,’ says Younghusband, unfolding his map.

‘The watershed from that range drains into an aquifer which opens there,’ says Nicolas. ‘You can see by the pattern of vegetation.’

‘Well, our casks are bone-dry, so a stop would suit us,’ Younghusband admits. ‘I’ll follow you down.’

The Pashtun servants gather brushwood, and shoot and butcher a wild goat while Nicolas puts up his tiny pup tent.

At nightfall, the air temperature drops to freezing. The sky is vast and moonless: a busy vault of stars streaked with the Milky Way, and Venus stands out as brightly as a pebble.

‘I left Peking in March,’ says Younghusband, his face yellow from the firelight. Sparks rise from the branches.

Everyone wants to be listened to, Nicolas thinks. He lets Younghusband tell his tale, how he crossed the Gobi by camel, how he travelled by moonlight, how he was bilked by a series of guides. At last, the Englishman is willing to admit to a few shortcomings. Younghusband is rightfully proud of his adventure. He is the first European to cross the Mustagh Pass. The vertiginous ice, which he negotiated in slippery leather footwear, without ice axes, and roped together with his native guides, reduced several of his party to gibbering wrecks. There is no denying the man’s hardiness and courage.