Red Herring – The phrase is used to describe something that provides a false or misleading clue, often in a detective story. In the eighteenth and nineteenth century Herring was one of the most widely caught fish in the seas around Britain. In those pre-refrigerated days Herring would be preserved by heavily salting and smoking the fish to ensure it was still edible by the time they arrived at market across English towns. This smoking process would turn the Herring a deep brownish red colour. Heavily smoked Herring would also have another notable characteristic, which was particularly strong and pungent smell.
To find out the origins of the well-known phrase we have to turn to hunting in the early 1800’s, or to me more accurate, hunt saboteurs. It’s true, there must have been an early version of the modern fox lover as on hunt days the strong smelling fish would be dragged along the hunt route and away from the foxes. This confused the hounds who followed the scent of the Red Herring rather than that of the fox, who would then scurry off to safety. So effective was this tactic that the phrase passed into common English language.
Extract from Money for Old Rope Parts 1 & 2