The word codswallop, primarily a British English term meaning "nonsense", is of uncertain origin.
The more popular etymology places the word's origins in the brewing
industry. In 1876, British soft drink
maker Hiram Codd
designed and patented a bottle
designed specifically for fizzy
drinks. Though his Codd-neck bottle
was a success in the fizzy drink industry, alcohol
drinkers disparaged Codd's invention, often saying it was only good for "wallop" (a slang
term for beer
in the late-19th century). The term soon became "Codd's Wallop" and was eventually used for anything of low-quality or rubbish.
Critics argue that this term, despite its popularity, is not likely to be the origin, as the first recorded use of codswallop was not until around the 1960s, over ninety years after the term for beer fell out of use. Also, if that were the derivation, we would expect to see it exist sometimes in the form of 'Codd's Wallop' and for an intermediate spellings of 'coddswallop' to be found.
Contrary to the critics quoted above many people with English ancestry in the working classes recall the use of the term in the 1930s & 1940s in northern England.
As the BBC series Balderdash & Piffle describes, the term appears in a 1959 episode of Hancock's Half Hour.