When first arriving at the crag I looked around fro an abseil stake and originally found one that looked relatively new, however, however after checking it found it to be loose and I could just pull it out of the ground. I then saw that there was another abseil stake further down which appeared to be fine. I then used this stake with a sling girth hitched at the very base backed up and equalised with a slung rock nearby as an anchor for an abseil. 6 People descended on atc's with prussik. After climbing Thane I topped out about 10m below the anchor and abseiled down. I believe in attaching my atc at the top I made the girth hitched sling on the stake move up about 2 inches. On the way down the stake gave, folding over and nearly completely disintegrating before the backup sling took the full wait of the abseil. I did not notice this until I got back to the top.