Billy Connolly’s signalman joke

In around 1980 I was a researcher at London Weekend TV when I was assigned to a pilot for a possible series starring Billy Connolly. It was a pretty lame idea and never made it, but it left me with wonderful memories of Connolly, one of the most naturally funny people I have ever met and lovely with it. His sheer joie de vivre made everyone around him feel better.