Al trails behind me, her face puce, her enormous backpack waving from side to side with each step she takes, the belt undone around her waist, her hands on her hips. Every dozen or so steps she stops, takes a puff of her asthma inhaler and continues on again. If I were Al, I’d ask to slow down or take more breaks, but she’s ox-like in her determination to get to the retreat before nightfall and hasn’t complained once. I hear the puff-puff of her inhaler and stop walking. That’s twice in the last five minutes.

“You okay?”

She shrugs off her backpack then bends forward and grips her knees with her hands. She sucks at the mountain air like a fish on a hook.

I put a hand on her shoulder. “Stand upright if you can. Leaning over like that squashes your lungs.” My brother Henry had asthma as a child, so her attack doesn’t faze me. Though the fact that we’re 3,500 metres above sea level and at least five and a half hours away from the nearest hospital does.

Al straightens up, puts her hands on her hips and cranes her chin towards the sky as she continues to gulp in air. Her cheeks are still a violent shade of red, but it’s not them I’m looking at. It’s her lips. They’re pink, not blue. That’s a good sign.

“Nice deep breaths,” I say. “Slowly. Don’t panic. In … and out … in … and out … Relax your shoulders. You’re tensing them because you’re scared. Relax your shoulders and exhale for as long as you can, then a nice deep breath in again.”

I can hear Daisy’s voice in my head as I speak, saying the exact same words to me a couple of months ago when I was in the grip of a panic atttack. We were in a crowded cinema, people filling every seat, and it was hot, really hot. We were watching a thriller Daisy wanted to see and each time the main character jumped, I jumped. Each time she saw shadows where there weren’t any I saw them too. As her world grew smaller and more claustrophobic, so did mine, and I became convinced that there wasn’t enough air in the cinema for everyone to breathe, and I had to get out.

“Everything okay, miss?”

Our guide nimbly picks his way back down the mountain towards us, his tiny rucksack strapped to his back. Shankar’s weather-beaten face is as lined as befits a man in his late forties, but he moves like a man twenty years younger.

“She breathe okay?” he asks as he reaches us.

“No. She’s not. I think the altitude might be affecting her asthma. Maybe we should go back down.”

“No!” Leanne says so loudly I jump. I hadn’t realised she and Daisy had joined us too.

“I’m sorry?”