[vetbike]

Being from Padiham ( left there in 1956), the story I heard was that people from Burnley considered themselves mentally superior to their sturdy, stockily built neighbors from Padiham and continually put them down.
The Padihamites had some posters printed and displayed in Burnley. These announced that a well known person was going to appear on a certain day at a spot near the old stepping stones and walk accross the river Calder. As this location was close to Burnley a large crowd appeared on the appointed day.
Naturally no one appeared, the Burnleyites having realized they had been duped , dispersed. From that day on they weren't allowed to forget they had been taken in by this joke. From then on they were known as "Burnley watterwalkers"!
My father used to tell this story, hope it helps to solve the puzzle.
Cheers, Vetbike.