in the late 19th and early 20th centuries, the concept of the flat was slow to catch on amongst the british middle classes, which generally followed the north european standard of single-family houses dating far back into history. those who lived in flats were assumed to be lower class and somewhat itinerant, renting for example a "flat above a shop" as part of a lease agreement for a tradesman. in london and most of britain, everyone who could afford to do so occupied an entire house—even if this was a small terraced house—while the working poor continued to rent rooms in often overcrowded properties, with one (or more) families per room.