A group of climbers were ascending Atenea (4c) to the left of my climbing party. The group contained one (somewhat) experienced climber and three novice climbers. The experienced climber encouraged the novice climbers to lead Atenea without ensuring they understood how to safely manage the anchor. The first novice climber to reach the anchor became confused and sought advice from the experienced climber who was belaying. The experienced climber offered a generic commentary on how to manage the anchor, although he was unable to observe the novice climber directly. The novice climber stated that she was unclear whether she had successfully dealt with the anchor but the experienced climber assured her all was fine. As he was encouraging her to sit back onto the rope to be lowered off, the novice climber lost her footing and fell from the anchor. (Members of my climbing party attempted to intervene but were ignored.) First, the experienced climber had left perhaps 4-5m of excess rope in the system to enable him to move freely around the base of the crag. Second, the novice climber had failed to set the anchor properly: her rope did not pass through any secure equipment. As a result, the novice climber fell from the climb, coming to rest more than halfway to the ground, hitting her head, arms and shoulders in the process. She was extremely distressed and was visibly in a state of shock. The experienced climber lowered her to the ground, at which point she lay on the ground wrapped in a foil blanket shaking severely. Her fellow climbers then continued climbing.