1. Main points

  • In mid-2017, the population of the UK was an estimated 66 million – its largest ever.

  • The UK population is projected to continue growing, reaching almost 73 million by 2041.

  • Sustained UK growth results from births outnumbering deaths (by 148,000 in 2017) and immigration exceeding emigration (by 282,000 in 2017).

  • In 2017, there were 27.2 million households in the UK and 19 million families.

  • In 2017, about 86% of the UK population were UK-born and about 90% were British nationals – down from about 89% and 93%, respectively, in 2007.

  • Although improvements in life expectancy have recently stalled, the UK population is generally living longer than it has before; babies born in 2015 to 2017 are expected to live 79.2 years if male (up 2.0 years since 2005 to 2007) or 82.9 years if female (up 1.4 years since 2005 to 2007).

  • The UK population is ageing – around 18.2% of the UK population were aged 65 years or over at mid-2017, compared with 15.9% in 2007; this is projected to grow to 20.7% by 2027.

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2. Statistician’s comment

“The UK population has doubled over the last 140 years, reaching a new high of 66 million people in 2017. We project there to be almost 73 million people in the UK by 2041.

“This growth is due to there being more births than deaths and more people moving to the UK than leaving.

“As well as growing, the population is also ageing. From looking at past patterns, we project that more than a quarter of UK residents will be aged 65 years or over within the next 50 years.”

– 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 like education, transport and healthcare. Estimates show growth in the size of the population, in the proportion of older people and in the numbers of families and households. This article brings together the main points from a number of current statistical bulletins to give an overview of the changing population of the UK.

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4. The UK population is at its largest ever

In mid-2017, the population of the UK reached a new high of 66 million, marking an increase of 0.6% from the previous year's total of 65.6 million – the lowest annual growth since 2004.

As seen in Figure 1, this was largely a continuation of recent trends; the UK population has grown year-on-year since 1982, with growth rates since 2005 consistent between 0.6% and 0.8%.

In future years, the UK population is set to grow further still. The projected population surpasses 70 million in 2029 and reaches 72.9 million by 2041 – increases of 6.1% and 10.4%, respectively, from 2017.

For most years on record, all four of the UK’s constituent countries (England, Northern Ireland, Scotland and Wales) have contributed to the UK’s annual growth. This was true again in the year to mid-2017, where contributions were as follows:

  • England’s population grew by 351,000 to 55.6 million (up 0.6% from mid-2016)

  • Northern Ireland’s population grew by 9,000 to 1.9 million (up 0.5%)

  • Scotland’s population grew by 20,000 to 5.4 million (up 0.4%)

  • Wales’s population grew by 12,000 to 3.1 million (also up 0.4%)

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-dependent

  • 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

In 2017, the number of households in the UK was 27.2 million, representing an increase of 6% from 2007. This 6% growth rate is similar to that of the UK population over the same period and thus the average household size has remained largely unchanged – at 2.4 people – throughout the decade.

Also, 2017 saw 19 million families living in the UK, which shows an increase of 8% from 2007:

  • 12.9 million families (68%) featured a couple who were either married or in a civil partnership

  • 3.3 million families (17%) featured a cohabiting couple (the fastest-growing family type)

  • 2.8 million families (15%) featured a lone parent with at least one dependent or non-dependent child

Meanwhile, young males were more likely to be living with their parents than young females (32% of males aged 20 to 34 years, compared with 20% of females aged 20 to 34 years). In general, young adults in the UK are more likely to be living with their parents now than in any time for which comparable data exists (1996 onwards).

Aside from living as a family, 7.7 million UK residents aged 16 years or over were living alone in 2017, which shows a 4% increase from 2007:

  • 3.9 million were aged 16 to 64 years, with the majority male (58.5%)

  • 3.8 million were aged 65 years and over, with the majority female (66.5%)

One explanation for this disparity is that older women are more likely to be widowed – outliving men on average and tending to be younger than their husbands to begin with.

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5. Why is the UK population growing?

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

The difference between the number of births and the number of deaths is referred to as “natural change”. When natural change is positive, there have been more births than 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 to the UK for more than 12 months) and the number of emigrants (people leaving the UK for more than 12 months) is termed “net migration”.

Natural change

In 2017, the UK experienced a natural change of 148,000, stemming from 755,000 live births and 607,000 registered deaths (Figure 2) – the highest number of deaths since 2003.

Note that the long-term trend for deaths is more stable than that of births. Due to the relative consistency in deaths, fluctuations in natural change have historically mirrored fluctuations in births.

For instance, Figure 2’s leftmost peak in natural change corresponds to the 1960s baby boom, which subsided in the 1970s. The second upturn in growth is then an “echo” of the first, whereby baby boomers themselves were having children of their own. Births peaked again more recently in 2012, at 813,000.

The gradual decline in deaths from 1985 to 2011 is regarded as a product of the “living longer” dynamic (see Section 6). With people during these years living longer than their predecessors had, numbers of deaths decreased accordingly.

Although the UK's mortality rates fell steadily across many previous decades, the rate of decline slowed significantly in the early 2010s for both males and females. Although a number of other countries have exhibited similar changes in this time, the UK’s slowdown is one of the most pronounced.

The UK’s statistics for the calendar year ending December 2017 break down as follows:

  • England’s natural change was 148,000 (with 647,000 births and 499,000 deaths)

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

  • Scotland’s natural change was -5,000 (with 53,000 births and 58,000 deaths)

  • Wales’s natural change was -1,000 (with 32,000 births and 33,000 deaths)

For individual time series on each constituent country, please explore our population health and reference tables (Vital statistics).

For a further breakdown of 2017’s deaths by cause of death, please see our interactive chart (for England and Wales) and National Records of Scotland vital statistics reference tables (for Scotland). The data for Northern Ireland will be available later this year, upon release of the Northern Ireland Statistics and Research Agency's 2017 Registrar General annual report (scheduled for early November).

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.

In 2017, the UK’s net migration was around 282,000, with around 631,000 people immigrating and around 349,000 emigrating (Figure 3).

Figure 3: UK immigration, emigration and net migration, year ending June 2008 to year ending March 2018

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Over the last two decades, immigration has increased from both EU and non-EU countries. For EU countries, these increases have generally coincided with expansions of the EU (where citizens of EU member states have freedom of movement between other EU member states, facilitating migration to the UK). These EU expansions, along with the other main migration events and trends, are chronicled in our interactive migration timeline.

Naturally, international migration also affects the nationality and country of birth compositions of the UK. Since 2004 (the year reporting began), the resident number of non-British nationals and non-UK-born individuals has grown year-on-year (Figure 4).

In 2017, about 86% of the UK population were UK-born and about 90% were British nationals – down from about 89% and 93%, respectively, in 2007.

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 2007. The largest annual increases were in the Romanian-born population (increasing by 80,000 to 390,000 in 2017) and Romanian nationals (increasing by 83,000 to 411,000 in 2017).

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6. The UK population is ageing

With ongoing advances in technology, healthcare and lifestyles, people in the UK are living longer on average than they might have in years gone by.

In 1997, around one in every six people (15.9%) were aged 65 years and over, increasing to one in every five people (18.2%) in 2017 and is projected to reach around one in every four people (24%) by 2037.

An estimated 18.9% of the population were under 16 years old and 62.9% were aged 16 to 64 years in 2017.

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 2066 there could be an additional 8.6 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 26.5% of the projected population.

The following interactive, Figure 5, shows how age structure differs by local authority over time.

Figure 5: Broad age group percentage of the UK population by local authority, 1997, 2007, 2017, 2027, 2037

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As the UK population lives longer, its old-age dependency ratio (OADR) also increases. This is the number of people of State Pension age (those aged 65 years and older) per every 1,000 of the working-age population (those aged 16 to 64 years old).

In mid-2017, the OADR of the UK was 289, which is up from 244 a decade prior. Without the planned re-balancing of the State Pension age, the UK’s OADR would be a projected 419 by 2041.

The increases in OADR coincide with falling fertility rates in the UK, which have declined from 1.87 children per woman in 2007 to 1.79 in 2016. 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.

Although females continue to live longer on average than males, the gap between sexes has decreased over the last 30 years, with males seeing greater increases in life expectancy. Improvements in life expectancy have recently stalled but the UK population is generally living longer than it has before; a baby born in 2015 to 2017 can expect to live to 79.2 years if male (up 2.0 years since 2005 to 2007) or 82.9 years if female (up 1.4 years since 2005 to 2007). Additionally, a projected 20.8% of all newborn boys and 31.7% of all newborn girls will now live to be centenarians.

The interactive population pyramids in Figure 6 show how the age and sex structures of the UK’s local authorities and constituent countries differ over time.

Figure 6: Population pyramids for the UK, by sex and single year of age, explorable by local authority and constituent country, 1997, 2007, 2017, 2027 and 2037

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  1. Figures for 1997, 2007 and 2017 are based on population estimates, whereas figures for 2027 and 2037 are based on population projections.

  2. 1997 data for ages 85 to 90 are not available individually for the local authorities of England and Wales, so the combined counts for 85-and-over are shown instead.

Ultimately, a longer-living population presents both opportunities and challenges for many policy areas and aspects of society.

While pressure is expected to mount on many sectors and services – such as social care, healthcare, transport, pensions and housing – our longer working lives, coupled with the growing population, ought to increase the size and productive capacity of the UK’s workforce. Although there are outstanding social well-being issues facing many older people – such as isolation and restricted mobility – we will have more years to spend with our families and friends. As a result we are likely to see increased community engagement and involvement in volunteering.

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Manylion cyswllt ar gyfer y Erthygl

Sarah Coates
Ffôn: +44 (0)1329 444661