These figures record the percentage of people living in households with more than one and a half people per room (not counting bathrooms and corridors). Note that this measure cannot be calculated for Scotland in 1931 or 1951.

The figures for 1931 are for 'families', not households, and the total number of families excludes those with more than five rooms. The figures seem to show a very clear geographical pattern, with the worst conditions concentrated into both urban and rural parts of the north-east of England. However, this pattern may be a result of the way the census measured crowding, by counting numbers of rooms rather than floorspace. To some extent housing in the north-east resembled that in Scotland, with fewer but larger rooms, while in the north-west of England people lived in terraced houses with lots of small rooms. There was also serious over-crowding in inner London: the twenty worst districts include Tower Hamlets, Islington and Southwark.

In 1931, three districts had over half their households living at over one person per room, but by 1951 only one had over a third. The worst districts were still concentrated in the north-east, but slum clearance schemes in some urban areas meant that the rural west midlands now appear as a problem area. In the 1950s and 1960s very active slum clearance programmes, planned construction of 'overspill' estates and new towns, and home-owning middle class families being able to afford better homes all led to great improvements: by 1971, only 6% of households in England and Wales had less than one room per person, compared to 21% in 1931 and 16% in 1951. The concentration of bad conditions in the north-east and London remained, although the north-east then saw remarkable improvement in its relative position during the 1970s.