1. Main points

  • In mid-2018, the population of the UK reached an estimated 66.4 million.

  • The UK population’s growth rate in mid-2017 and mid-2018, at 0.6%, was slower than any year since mid-2004.

  • Long-term international migration to and from the UK has remained broadly stable since the end of 2016 and has also continued to be the main driver of the UK’s population growth.

  • In 50 years’ time, there is projected to be an additional 8.2 million people aged 65 years and over in the UK – a population roughly the size of present-day London.

  • After decades of improvement to life expectancy, the latest figures show a slowdown in improvement – life expectancy at birth remained at 79.2 years for males and 82.9 years for females in 2015 to 2017.

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2. Statistician’s comment

“In 2018, the UK population reached 66.4 million people and migration remained the main driver to population growth.

“The structure of the UK’s population is changing: people living longer and having fewer children means the age structure is shifting towards later ages. The ways in which people live are also changing with cohabiting families the fastest-growing family type and more young adults living with their parents.”

Sarah Coates, Centre for Ageing and Demography, Office for National Statistics

Follow the Centre for Ageing and Demography on Twitter @RichPereira_ONS and the Centre for Migration on Twitter @JayLindop_ONS

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3. Introduction

Understanding the size and characteristics of the UK population is vital when it comes to planning and delivering services such as education, transport and healthcare. As the UK’s population continues to grow there has been a shift in the age structure towards later ages meaning we have an ageing population. In addition, our living arrangements are changing; more young adults are living with their parents and increasing numbers of people are living alone. This article brings together the main points from several bulletins to help understand how the UK’s population is changing.

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4. The UK’s population continues to grow, but at a slower rate than previously

The UK population has grown year-on-year since 1982 as seen in Figure 1. The 2018 mid-year population estimates release showed that the population of the UK reached 66.4 million, up from 66.0 million in mid-2017. This population growth marks an increase of 0.6%, or an addition of 395,000 people, between mid-2017 and mid-2018 – the same rate of population growth as in the previous year. Growth in the years to mid-2017 and mid-2018 were slower than in any year since mid-2004.

Despite the recent slowdown in population growth rates, the UK population is set to increase further still. The 2016-based national population projections showed that the projected population surpasses 70.1 million by mid-2029 and reaches 72.9 million by mid-2041 – increases of 5.5% and 9.7%, respectively, from mid-2018.

All four of the UK's constituent countries (England, Northern Ireland, Scotland and Wales) continue to contribute to the UK's annual growth. England’s population has continued to grow at a faster rate than the rest of the UK in the year to mid-2018. The contributions from all the four constituent countries are as follows:

  • England's population grew by 358,000 to 56 million (up 0.6% from mid-2017)

  • Northern Ireland's population grew by 11,000 to 1.9 million (up 0.6% from mid-2017)

  • Scotland's population grew by 13,000 to 5.4 million (up 0.2% from mid-2017)

  • Wales's population grew by 13,000 to 3.1 million (up 0.4% from mid-2017)

Figure 2 displays how the population growth rate also differs at a local level. The four fastest-growing local authorities are in London. The City of London’s population has increased by the largest proportion in the last five years. However, this local authority continues to have the second-smallest population within the UK, after the Isles of Scilly.

Other areas that have shown large proportional population increases between mid-2013 and mid-2018 include:

  • Tower Hamlets’ population increased by 16% (from 274,000 to 318,000)

  • Camden’s population increased by 14% (from 230,000 to 262,000)

  • Westminster’s population increased by 13% (from 225,000 to 255,000)

Many of the 23 local authorities with decreasing populations over the last five years are in coastal areas with older populations. Ceredigion (in Wales) has shown the largest proportional decrease in population over the last five years with a 4% decrease between mid-2013 and mid-2018, falling from 75,800 to 73,000. Inverclyde (in Scotland) and Copeland (in the North West of England) had the second- and third-largest proportional decreases (3% and 2%, respectively).

Figure 2: The population growth rate differs at a local level

Population growth by local area mid-2013 to mid-2018, local authorities in UK

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Families and households

In this section, the following definitions are used:

  • a family is a married, civil partnered or cohabiting couple with or without children, or a lone parent with at least one child, who live at the same address; children may be dependent or non-dependent1

  • a household is one person living alone, or a group of people (not necessarily related) living at the same address who share cooking facilities and share a living room, sitting room or dining area; a household can consist of a single family, more than one family, or no families in the case of a group of unrelated people

As the UK’s population grows, so does the number of families and households. In 2018, the number of households in the UK was 27.6 million, representing an increase of 7% from 2008 (25.9 million).

In 2018, there were 19.1 million families living in the UK, which shows an increase of 8% from 2008 (17.7 million):

  • there were 12.8 million married couple or civil partnership families (67%)

  • there were 3.4 million cohabiting couple families (18%)

  • there were 2.9 million lone parent families (15%)

Cohabiting couple families are the fastest-growing family type; since 2008, there have been an additional 700,000 cohabiting couple families (a growth rate of 25.8% over this period). Meanwhile, more young adults are living with their parents. In 2018, the first age at which more than 50% of young people left the parental home was 23. Two decades earlier, more than 50% of 21-year-olds had already left home. Young men aged 20 to 34-years-old living in the UK are more likely than young women to be living with their parents (31% and 20% respectively).

In addition, we are seeing increases in the numbers of people who are living alone – between 2008 and 2018, there has been a 6% increase (from 7.5 million to 8.0 million). This increase was driven primarily by the increase in the number of older men living alone; a 55% increase for men aged 65 to 74 years and a 20% increase for men aged 75 years and over. In 2018, nearly half of those living alone (48%) were aged 65 years and over, and more than one out of every four (27%) were aged 75 years and over.

Notes for: The UK’s population continues to grow, but at a slower rate than previously
  1. Families and household statistics explained provides further explanation of the families and households definitions that are used.
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5. Migration to the UK has been the main driver of population growth since the 1990s

Change in population size has four components: births, deaths, immigration and emigration.

The difference between the number of births and deaths is referred to as “natural change”. When natural change is positive, there have been more births and deaths in the considered timeframe. When it is negative, there have been more deaths than births.

The difference between the number of immigrants (people moving into the UK for more than 12 months) and the number of emigrants (people moving out of the UK for more than 12 months) is termed “net migration”.

Natural change

In 2018, the UK experienced a natural change of 115,000 with 731,000 live births and 616,000 deaths 1 – the lowest level of natural change since 2003.

Analysis of the births data in England and Wales in 2018 shows that the number of live births was the lowest recorded since 2005 and the birth rate was the lowest ever recorded (11.1 live births per 1,000 total population). Analysis of deaths registered in England and Wales: 2018 shows the highest number of deaths since 1999 – however, when taking into account the age and size of the population, death rates have remained more or less stable since 2011.

The natural change data presented in Figure 3 are for calendar years and so will differ from the natural change component of change for the population estimates, which are calculated for mid-years (reference date 30 June).

Fluctuations in natural change have historically mirrored fluctuations in births. For example, Figure 3’s left-most peak in natural change corresponds to the 1960s baby boom, which subsided in the 1970s. The second upturn in natural change is an “echo effect” of the first, whereby baby boomers are having children of their own. Births peaked again more recently in 2012, at 813,000. Since 2012, there has been a reduction in the number of live births of 10% to 731,000, this reduction is mirrored in the reduction in natural change.

The long-term trend in the number of deaths is more stable than in the number of births. The total number of deaths peaked in 1976 at 681,000. Much of the gradual decline in the number of deaths from 1985 and 2011 has been driven by people living longer. Then as a larger number of people reach older ages there has consequently been a general increase in the number of deaths since 2011, thus contributing to the decline in natural change.

The breakdown of natural change for England, Wales and Scotland for the calendar year ending December 2018 is as follows:

  • England’s natural change was 120,000 (with 626,000 births and 506,000 deaths)

  • Wales’s natural change was negative 4,000 (with 31,000 births and 36,000 deaths)2

  • Scotland’s natural change was negative 7,000 (with 51,000 births and 59,000 deaths)3

Data for Northern Ireland are available for the calendar year ending December 2017:

  • Northern Ireland’s natural change was 7,000 (with 23,000 births and 16,000 deaths)

For a detailed time series on each country, please see Births in England and Wales summary tables, Death registration summary tables – England and Wales, and Scotland’s Vital Events Reference Tables 2018. Updated data for Northern Ireland will be available later this year, upon release of the Northern Ireland Statistics and Research Agency’s 2018 Registrar General Annual Report.

The average number of children a woman has during her lifetime is declining

Total fertility rate (TFR) is the hypothetical average number of children a woman would have in her childbearing years if she were to experience the age-specific fertility rates of the year in question. TFR of about 2.1 children per woman is the number of children a woman would need to have to sustain current population levels (ignoring migration) – also known as the replacement fertility level.

Figure 4 displays how TFR has changed over time. The TFR hit an all-time low in 2001 for the UK with an average of 1.63 children per woman. Following this low, the TFR increased and stabilised at an average of 1.92 children per woman in 2012. In 2013, there was a substantial drop in UK TFR to 1.83. The TFR has since continued to decline – and in 2017, the average number of children per woman was 1.74.

Age-specific fertility rates show a decline in fertility rates at younger ages and rises at older ages. Between 2016 and 2017, all age groups, except women aged over 40 years, have seen decreases in fertility rates. Women aged over 40 years have continued to have higher age-specific fertility rates than those aged under 20 years.

Net migration

For the majority of the 20th century, natural change was the main driver of UK population growth, with net migration a secondary factor. In the 1990s, however, net migration increased in influence and has been the main source of growth since 1998.


Preliminary adjustments have been made to international migration estimates based on the findings from research into the coherence between migration data sources. The findings in this section are based on the preliminary adjusted estimates for the years in which they are available. Otherwise, the Long-Term International Migration (LTIM) estimates remain our best available estimates. We will continue to develop our adjustment approach in our future reports.

Long-term international migration data show that migrants continue to add to the UK population, as an estimated 226,000 more people moved to the UK with an intention to stay 12 months or more than left in the year ending March 2019 (net migration). This is lower than the recent peak of 343,000 in the year ending June 2015, however, levels have remained broadly stable since the end of 2016. Over the last year, 612,000 people moved to the UK (immigration) and 385,000 left the UK (emigration) (Figure 5).

Figure 5: Long-term immigration, emigration and net migration have remained broadly stable since the end of 2016

Long-term international migration, UK, year ending Jun 2009 to year ending March 2019

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Although overall migration levels have remained broadly stable since 2016, there are different patterns for EU and non-EU citizens. EU net migration has decreased since 2015, following a three-year period of increase. Non-EU net migration has remained broadly stable over the last year, following a gradual increase since 2013.

Decisions to migrate are complex and a person’s decision to move to or from the UK will always be influenced by a range of social and economic factors.

Naturally, international migration also affects the nationality and country of birth compositions of the UK. Since 20044, the resident number of non-British nationals and non-UK-born individuals has grown year-on-year (Figure 6). It is important to note that country of birth refers to the country a person was born in, so this will not change, whereas nationality is self-reported by the respondent when they are interviewed so this is subject to change 5.

In 2018, about 85.7% of the UK population were UK-born and about 90.7% were British nationals – down from about 88.9% and 93.1%, respectively, in 2008.

Poland remains the most common non-UK country of birth, having taken over from India in 2015, and Polish has been the most common non-British nationality in the UK since 2008. Despite this, the largest annual decrease was seen in the Polish-born population (decreasing by 90,000 to 832,000 in 2018). Poland has also seen the largest annual decrease in nationals (decreasing by 116,000 to 905,000 in 2018).

The largest annual increases in 2018 were in the Italian-born population (increasing by 21,000 to 253,000) and Brazilian nationals (increasing by 19,000 to 59,000).

Notes for: Migration to the UK has been the main driver of population growth since the 1990s
  1. The 2018 figure has been estimated using births and deaths from 2017 for Northern Ireland; the 2018 figures will be available later this year. 2018 figures have been used for England, Scotland and Wales.

  2. Totals may not sum due to rounding.

  3. Totals may not sum due to rounding.

  4. 2004 was the year reporting of nationality began – for the Annual Population Survey.

  5. Full details of definitions can be found in International Migration terms, definitions and frequently asked questions.

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6. The UK’s population is ageing

Like many other countries, the UK’s age structure is shifting towards later ages. By 2050, it is projected that one in four people in the UK will be aged 65 years and over – an increase from approximately one in five in 2018. This is the result of the combination of declining fertility rates and people living longer. While for some living longer may be a cause for celebration, the ageing population has implications on several policy areas.

The population aged 65 years and over is growing faster than other age groups

The UK’s age structure is determined by trends in fertility and mortality. Generally, both fertility and mortality rates have been declining in the UK. Thus, with less to counterbalance the living longer dynamic, the overall age structure of the UK has tipped further towards the later-life age groups.

According to projections, the population share of later-life age groups is set to increase further in future years too. By 2041, the 1960s baby boomers will have progressed into their 70s and 80s, and by 2068 there could be an additional 8.2 million people aged 65 years and over in the UK – a population roughly the size of present-day London. This would take the UK’s 65 years and over age group to 20.4 million people, accounting for 26.4% of the projected population.

In 1998, around one in six people were 65 years and over (15.9%), this increased to one in every five people in 2018 (18.3%) and is projected to reach around one in every four people (24.2%) by 2038.

Comparatively, an estimated 20.5% of the population were under 16 years old in 1998, decreasing to 19.0% in 2018 and is projected to decline to 17.4% by 2038. In 1998, 63.6% of the population were aged 16 to 64 years old, down to 62.7% in 2018 and projected to decline to 58.4% in 2038.

Within the UK, the older population make up higher proportions of the populations of rural and coastal than urban areas. The following interactive, Figure 7, shows how age structure differs by local authority over time.

Figure 7: Coastal areas have a higher proportion of the population who are aged 65 years and over

Broad age group percentage of the UK population by local authority, 1998, 2008, 2018, 2028, 2038

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  1. Data for 1998, 2008 and 2018 are based on population estimates, for 2028 and 2038 data are based on population projections.

  2. For Northern Ireland’s local authorities in 1998, the data used is for Northern Ireland as a country. This is because the data collected in 1998 is not comparable at a local authority level.

Figure 8 provides an interactive tool that will show you how the age and sex structure of a population can vary across the UK’s local authorities and constituent countries.

Figure 8: The age and sex structure of a population varies by local area

Population pyramids for the UK, by sex and single year of age, explorable by local authority and constituent country, 1998, 2008, 2018, 2028, 2038

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  1. Data for 1998, 2008 and 2018 are based on population estimates, for 2028 and 2038 data are based on population projections.

  2. 1998 data for ages 85 to 90 years are not available individually for local authorities of England and Wales, so the combined counts for 85-and-over are shown instead.

One traditional measure used to consider the impact of an ageing population is the old-age dependency ratio (OADR) – this measures the number of people of pensionable age and over per 1,000 people aged 16 years to State Pension age (SPA). In 1998, the OADR was 300; by 2008 this had increased to 307, suggesting increased dependency. In 2018, the OADR decreased to 295. However, the UK’S OADR is projected to increase into the future, reaching 360 by 2038.

While there are increases to the number of people above State Pension ages, we are seeing the number of people aged 65 years and over in work higher than ever before. Our June 2019 analysis looks at an alternative measure that takes into account the contribution of older workers. Using this alternative measure, the analysis found that economic dependency has shown an improvement, despite the population becoming older. While the main explanation is changes in economic activity, immigration of those of working age has also had some effect.

Improvements in life expectancy are slowing down

After decades of steady improvement in the UK’s life expectancy, the latest figures from the National life tables show a slowdown in improvement of life expectancy in the UK. Life expectancy at birth did not improve in 2015 to 2017, when compared with 2014 to 2016 life expectancy, and remained at 79.2 years for males and 82.9 years for females. Despite no recent improvement to life expectancy, the latest figures still show the highest life expectancy the UK has seen.

On average, females continue to live longer than males, however, the gap between the sexes has decreased over the last 30 years with males seeing greater increases in life expectancy.

Within the UK, life expectancy at birth declined by 0.1 years between 2014 to 2016 and 2015 to 2017 for males and females in Scotland and Wales and for males in Northern Ireland. Life expectancy at birth remained unchanged from 2014 to 2016 for females in Northern Ireland and males and females in England.

In addition to the National life tables, we continue to monitor and report on the slowdown in life expectancy and mortality improvements in a number of publications. As we continue to see a slowdown in life expectancy improvements we will continue to analyse the data further to understand more about the causes behind this.

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