1921 Census of England and Wales, General Report with Appendices, Table 90 : " Comparison of Night and Day Populations. London".

Area.* Night
Increase or decrease (—)
during the day.
Amount. % of Night
City of London 13,709 436,721 423,012 3085.70%
Inner Boroughs 1,035,764 1,422,119 386,355 37%
Outer Boroughs 3,435,050 3,130,169 -304,881 -8.90%
Outer Ring 2,995,678 2,596,011 -399,667 -13.30%

*The inner and outer boroughs are shown in Table XCI. The outer ring is that portion of Greater London—the area covered by the City and Metropolitan Police Districts—outside the Administrative County.

In addition to the numbers shown for the City of London and the Inner and Outer Boroughs there were 6,876 cases in which the place of work was returned as London only and which could not therefore be allocated to any group of boroughs.