The forecast said cloud base 600 metres and it was not lying. We left Edale in bright, unhelpful sunshine and walked into grey about twenty minutes above Upper Booth.

Jacob's Ladder is a staircase argument you have with yourself. It is not long. It is not technical. It simply keeps going, and the view that normally repays it was, today, the inside of a cloud.

On the plateau the thing nobody tells you is how quickly the ground stops helping. Kinder is a maze of peat groughs — channels cut two or three metres deep, all of them looking identical, none of them running where you'd like. In clear weather you navigate off the edge and the tors. In cloud you navigate off a bearing and a count of your own paces, and you discover exactly how much you trust both.

We got it right for about a kilometre and then wrong by a hundred metres, which on Kinder means climbing out of a grough you didn't mean to enter and re-taking the bearing while trying not to sound rattled.

The Downfall announced itself by sound before sight. Not much water, but enough, and the updraught doing its trick of throwing the whole fall back over the lip in a fine drift. Two other walkers appeared out of the murk going the other way, said the single syllable that passes for conversation up there, and vanished again.

Down by Grindslow Knoll the cloud broke for about ninety seconds and the whole valley opened underneath us — fields, the railway line, a train going somewhere — and then closed again like someone had shut a door.

Seven hours, twenty-one kilometres, one wrong grough. Boots still drying.