Three climbers who all had previous outdoor sport climbing experience were climbing in a group. Due to one climber (Climber B) having less experience than the others, Climber A led the route first, placing opposed quickdraws on the anchor bolts to lower off. Climber B then led the route and used the in situ quickdraws to lower. Finally Climber C led the route with the intention of cleaning the anchors and lowering off the fixed gear. Climber C reached the anchor, which was situated on a large, sloping ledge (approximately 4-5 metres above the highest bolt on the route) and shared with an adjacent route. The climber was using a knotted sling and screw gate carabiner as a safety system, and as the anchor was positioned above head height, had to reposition the screw gate on the knotted sling to allow it to reach the anchor, which required the carabiner to be taken off the sling and reattached. The screw gate was attached to the anchor and locked (confirmed later when gear was retrieved). The climber weight tested the sling then indicated they were safe to the belayer (who kept the climber on belay), before removing the quickdraws from the anchor. Upon leaning back to attach the quickdraws to their harness, the sling released from the screw gate and Climber C stumbled backwards and fell approximately 10-12m down the series of ledges on the climb. The fall was arrested by the belayer approximately 1 metre above the ground. Bystanders assisted the other two climbers in administering first aid and calling the emergency services. The fallen climber was attended by paramedics and transferred to Glan Clwyd A&E by ambulance. After a full body CT scan, the climber was confirmed to have no broken bones but suffered cuts/abrasions, very severe bruising, whiplash and a sprained ankle.