The UK population is growing. Until the mid-1990s this growth was mainly due to the number of births exceeding the number of deaths and this natural change is set to continue. Nonetheless, low numbers of children born and low mortality rates have both contributed to population ageing. There is a declining proportion of the population aged under 16 and an increasing proportion aged 65 and over.

Net international migration into the UK from abroad has been an increasingly important factor in population growth. Around one in twelve of the UK population were born overseas. Around a half of international migrants are aged between 25 and 44 and the overseas-born population is more concentrated in the working age group than is the UK-born population.