The term brown bread is widely used by many people in England, Ireland, Scotland, Wales, Australia, and other English Speaking communities to describe the death of someone! It may look a rather bizarre and uncaring on the face of it but it usually relates to someone that is not a close relative! It might for instance be a known actor or public figure for example, someone could have said, “did you hear about Winston Churchill? he’s brown bread”!
It is generally known as Cockney rhyming slang, and is said to have been created in English prisons many years ago as a way for prisoners to communicate without prison guard’s eves dropping on their conversations! The term Cockney describes someone who is born in the East end of London, a part of the city where many of the prisoners came from, it was a mainly poor high crime area.
Today people still use rhyming slang in daily conversations without thinking of the origins! One of most common one being “use you loaf” which relates to using your intelligence, and loaf of bread meaning head!
Examples: Apples and pears means stairs, trouble and strife means wife, dog and bone means phone,
Loaf of bread means head, mince pies means eyes, plates of meat means feet, brown bread means dead.