Clear sunny day - easy route (4a).

Earlier in the day the climb had been set up as a top rope for friends and family. The rope - at 30m - was long enough to just use quickdraws as top anchor but the anchor had been extended by 2x120cm slings with screw gate carabiners through which the rope passed. This left plenty of slack for easy belaying. A knot had been put in the belay end of the rope at the start of the day.

When all climbing had finished I climbed the route to clear it. On arriving at the anchor I attached with 2x slings and proceeded to break down the anchor slings and retie. However instead of using the untie/retie method I put a loop through the lower off rings and used a figure of eight on the bight to attach through a screwgate to my belay loop. I did not consider the cumulative effect of removing the sling anchor extenders and using this retie method on the length of rope available for lowering off. It was now too short but I had not noticed.

On lowering off I was approx 1.5m off the ground above a relatively steep scree slope, directly above the belayer, when he happened to notice that he had approx 10cm of dead rope left. The knot had been removed some time during the day. Luckily he was using a gri-gri which had locked off. I climbed down the last 1.5m. If he had not noticed I could have fallen backwards straight onto him and taken us both down the slope.