At this time he (= Bernard Shaw) and I were involved in a bicycle accident, which I feared for a moment might have brought his career to a premature close. He was only just learning to ride a bicycle, and he ran into my machine with such force that he was hurled through the air and landed on his back twenty feet from the place of the collision. However, he got up completely unhurt and continued his ride; whereas my bicycle was smashed, and I had to return by train. It was a very slow train, and at every station Shaw with his bicycle appeared on the platform, put his head into the carriage and jeered. I suspect that he regarded the whole incident as proof of the virtues of vegetarianism.
Source: Bertrand Russell: Bernard Shaw, 1953