three-quarters of a million to England and Wales being offset by net losses from Scotland and Northern Ireland. This net gain was the balance of a large outward movement mainly of British subjects emigrating, mostly since 1945, to Canada, Austraha, New Zealand and South Africa, and a larger inward movement mainly of aliens from Europe, many of whom were refugees seeking sanctuary in Britain. Over the whole 150 years since the beginning of the nineteenth century, net migration has been markedly outward. About 25 million persons born in the British Isles are estimated to have gone overseas in this period to settle in the United States and Commonwealth countries. On the other hand large numbers of Europeans, mainly Russians, Poles and Germans, have entered the British Isles during the last 80 years. The net loss by migration since 1871 from the present area of the United Kingdom is about 3½ million,
Age Distribution. The continuous fall in death rates and the low inter-war birth rates are beginning to increase the proportion of elderly people, and thus to reduce the proportion of the working population to the total population. The small age groups born between the wars have been and are still coming to maturity. The size of the age groups reaching retirement age increases yearly, as these groups were born during a period of rapidly expanding population. The continuing fall of the death rate in all age groups has still further increased the number of old persons. Moreover, the higher birth rates since 1942 have arrested the compensating fall in the number of dependent children. In December 1952 the age distribution of the United Kingdom was estimated as follows:
| Under 15 | 22-6 per cent |
| 65 and over | 11.0 per cent |
| 15 to 64 | 66.4 per cent |
During the present decade the population of Britain will have abnormally large numbers aged between 40 and 50. Assuming that mortality rates continue to fall, and disregarding migration, it can therefore be shown that:
(1) over the next 15 years the population of working age will remain roughly constant;
(2) the number of old people (over 65) will increase over the next 30 years by about three million.
These predictions are independent of the future course of births.
Sex Ratio. Total births of boys usually exceed those of girls by about 5 per cent, but owing to the higher stillbirth rate and infant mortality among boys, and the higher male death rates in all age groups, women have for the past 100 years outnumbered men from adolescence onwards and in the total population. Their predominance increases with age and is now nearly 50 per cent among persons over 70 years of age.
The fall in mortality has affected the sex ratio by increasing the proportion of old persons in both sexes, which has made female predominance in those age groups a weightier factor in the sex ratio of the population as a whole. At the same time there has been a slight rise in the proportion of boys among children under 15 years of age. The proportion of females to males in the total population has not varied greatly, however, as these two effects have counterbalanced each other. At present there are six per cent more females than males.
If the future brings a further reduction in family size, the decline of annual births will become rapid, with serious effects on the trend of population. Fear of this eventuality was an important factor in a growing concern with population problems, which led to the appointment in March 1944 of a Royal Commission on Population to inquire into the facts concerning British population trends, their causes and probable consequences; and to 'consider what measures, if any, should be taken in the national interest to influence the future trend of population'.
