"But the laugh of the day came when Mr. Eric Hallas, outside manager for Offiler's Brewery, Ltd., was asked to define a public bar. His technical explanation obviously still left the justices slightly puzzled, so the Clerk (Mr. H. Wilfrid Skinner) helped out.
"Is it not the difference between spittoons and no spittoons?" he asked.
"Exactly," agreed Mr. Hallas."
Derby Daily Telegraph - Friday 23 June 1950, page 4.
I wonder when that changed? I can't ever remember seeing a spittoon in a pub. And I always used to hang around in the public bar.