He was standing in the river which was quite high and he had just changed his fly. Unfortunately he dropped his fly wallet and, as he bent over quickly to grab it, the water washed into the top of his chest waders and he was swept down the river.
Off he went with his wallet in one hand and his rod in the other. Sensibly he was wearing a life preserver, but the current was strong and he went down through two pools, Black Strand and Doocotes, before getting out beside the old Tweed Bridge.
As he climbed out onto the bank he felt a tug on his line and realised he had a fish on. He then landed a nice 10lbs fish before heading off for a hot bath and a fortifying celebratory drink.