He was virtuoso harmonica player who became famous for *not* playing his harmonica on most episodes of the Morecambe and Wise shows: he would rush onto the stage in the middle of their act and start playing, only to be cut off after a few bars by
Eric Morecambe saying "Not now, Arthur", or else he would come on after the closing credits and the screen would cut to the continuity announcer just after he started playing.