- The charts shows the total population estimates for the usually resident population in the United Kingdom.
- The usually resident population accounts for long-term international migrants (people who change their country of usual residence for a period of 12 months or more) but do not account for short-term migrants (people who come to or leave the country for a period of less than 12 months). This approach is consistent with the standard UN definition for population estimates which is based upon the concept of usual residence and includes people who reside, or intend to reside, in the country for at least twelve months, whatever their nationality.
- Estimates for 1939 and 1948 to 1952 refer to the home population which includes both civilians and home armed forces resident in the stated country, not any UK armed forces posted abroad.
- Estimates for 1930 to 1938 and 1943 to 1947 include civilians and all UK armed forces posted at home and abroad.
- Estimates for 1940 to 1942 include civilians resident in the stated country, not any armed forces either posted home or abroad.
For further detail on methodology access the ONS population estimates webpage