It was the lead climbers 1st route to Fair Head - the belayer had led the route before and led P1 this time. Near the top of P2 the leader encountered a loose rock - he later said it was a stone he brushed against rather than one he weighted. He yelled a warnign but could not hold the stone and the 3 on the belay ledge could not avoid it, It traveled down ca 15-20m and hit the belayer on shoulder and back. The belayer managed to maintain grip on the lead climbers rope. Another climbing pair were on the belay ledge and took over the belay. A paramedic on a neighboring climb abseiled down, checked the injured climber and they were both taken to the top of route using an assisted hoist. The climber was taken to local hospital with deep cut to arm (requirement stitches and tetanus shot) and possible fractured rib but released later that day