This afternoon, one of the members of the book club I'm in brought up the phrase 'cock and bull story'. He said the phrase originated in England, where two pubs were close enough together that the same patrons would go to both, and typical "fish tales" were told. One was called the Cock and the other, the Bull.

Does anybody have any reliable info. on this origin?

Apparently not. Michael Quinion pooh-poohs the neighboring pub story but has nothing to offer in its place. Dave Wilton is silent on the matter.

Found this on 'The Straight Dope'

The more likely explanation, Word Detective ventures, is that the expression refers to old fables featuring talking animals, a notion that the French "cock to donkey" tends to corroborate. We've seen similar usages arise in our own time, leading me to think Word Detective has it right and that alternative theories are not just cock and bull stories but--dare I say it?--mickey mouse.

The Cock and Bull is a popular franchise of pubs down here where you can grab a steak and a pint o dark for lunch or dinner.