I was climbing on the newly cleaned north buttress in the gorge. We’d done two HVS’s already and the choice was between fitting in another climb in or heading for dinner. I elected to lead Carlos J G, what looked like a short, well protected layback crack. I got one good wire in on the right and then, reluctantly, what I though was a good no.1 cam in a solid hand jam. I managed to place another very dubious small wire in quite a parallel crack (small enough that I had no cams that would fit) and moved up. I then placed another poor wire in a dubious shallow placement and then finally what I thought was a bomber wire slotted rightwards into a crack (so that I could not see it from straight on). I pulled hard to seat the wire but rather than biting into the crack it flew straight out of the bottom depositing me, back first, on the floor with all three of the pieces of gear (excluding the too low first piece) there with me. I managed to hobble home and after a visit to A&E this morning found out luckily that it is just soft tissue damage and nothing is broken.