UK Population in 2026: 67.6 Million, Ageing, and Dependent on Migration for Growth

How Big Is the UK Population?

The United Kingdom had a population of approximately 67.6 million in mid-2023, according to the Office for National Statistics (ONS). This makes the UK the third most populous country in Europe, behind Germany (approximately 84 million) and France (approximately 68 million). The UK is also the 21st most densely populated country in the world, with an average of 281 people per square kilometre — significantly higher than France (120/km²) and Germany (237/km²), reflecting the UK's relatively compact geography and historically urbanised population.

Regional breakdown

The UK's population is not evenly distributed across its four constituent nations. England dominates, accounting for roughly 85% of the total UK population, whilst Scotland, Wales, and Northern Ireland each contain considerably smaller shares. The south-east of England — and Greater London in particular — is by far the most densely populated region, with London alone home to approximately 9 million people.

Historical context

The UK's population has grown substantially across the twentieth century and into the twenty-first. At the turn of the twentieth century, around 1900, the population of the United Kingdom was approximately 38 million. By 1950 it had reached around 50 million, and by 2000 approximately 59 million. The pace of growth accelerated markedly in the 2000s and 2010s, driven by higher birth rates among migrant communities, increased life expectancy, and rising net migration — particularly following EU enlargement in 2004.

On current ONS principal projection trajectories, the UK population is likely to cross 70 million around 2030. Whether it does so on schedule depends heavily on migration policy — as will be explored later in this article. Population density in the UK is already among the highest in Europe, and continued growth is placing sustained pressure on housing supply, green belt land, transport infrastructure, water resources, and public services in the most congested regions.

Birth Rate: Falling Below Replacement

The most striking demographic story in the UK over the past decade has not been migration — it has been the collapse in the birth rate. The total fertility rate (TFR) — the average number of children a woman is expected to have over her lifetime — fell to just 1.49 in 2022, the lowest level since records began, according to ONS vital statistics. The replacement rate — the level at which a population sustains itself without migration — is 2.1. The UK has been below replacement rate since the early 1970s, but the recent decline to 1.49 marks a new low.

What is driving the decline?

The causes of declining fertility are structural and reinforcing. Women in the UK are having children later in life — the mean age at first birth has risen to approximately 29 — partly because extended education and early career development take priority during the years of peak fertility. Rising housing costs mean that many couples cannot afford a family home until their thirties. The cost of childcare in the UK is among the highest in the developed world: a full-time nursery place for a child under two costs approximately £14,000–£18,000 per year in many parts of England, absorbing a large share of a second income and frequently making it economically rational for one parent to leave the workforce entirely. Cultural shifts — including greater individual autonomy, higher expectations of parenting quality, and changing attitudes to family formation — also play a role.

How does the UK compare internationally?

The UK's fertility rate of 1.49, while the lowest in British history, is not exceptional by European standards. Many comparable countries have experienced similar or more severe declines. Italy and Spain have fertility rates below 1.3 — meaning each generation is less than two-thirds the size of the previous one. South Korea's TFR in 2023 fell to an extraordinary 0.72, making it an extreme outlier globally. The UK sits broadly in the middle of the European range.

Implications for the workforce and public finances

A falling birth rate has profound long-run economic consequences. Each generation entering the workforce is smaller than the previous one, meaning fewer workers to pay taxes, fewer people to consume goods and services, and fewer contributors to pension schemes and healthcare systems. In a pay-as-you-go pension system — such as the UK's state pension — current workers fund current retirees. A shrinking working-age population relative to a growing retired population creates a structural fiscal imbalance that worsens over time. The OBR's long-run projections model precisely this dynamic, and find that without policy reform, age-related spending will consume a growing share of GDP for decades.

Death Rate and Life Expectancy

Approximately 590,000 people die in England and Wales each year, according to ONS mortality statistics. Northern Ireland adds approximately 16,000 deaths annually (NISRA data), and Scotland approximately 57,000 (National Records of Scotland), giving a UK-wide total of roughly 660,000 deaths per year. This figure is broadly stable but has been affected by the COVID-19 pandemic, which caused an estimated 200,000 excess deaths cumulatively during 2020–2022.

Life expectancy

Life expectancy at birth in the UK stands at approximately 79.0 years for males and 82.9 years for females, based on 2020–2022 ONS period life tables. These figures represent a slight decline from pre-COVID-19 peaks — the pandemic disproportionately affected older and more vulnerable groups, temporarily reversing decades of incremental improvement in life expectancy. Whether this decline is permanent or temporary remains a question for ongoing ONS analysis.

Healthy life expectancy — the number of years a person can expect to live in good health — is substantially lower than total life expectancy. ONS estimates suggest that on average, the last 16 to 20 years of life are spent with significant health limitations. This gap between total and healthy life expectancy is a major driver of NHS demand and social care costs, because people living longer with chronic conditions require sustained health and care support for extended periods.

Dementia overtook ischaemic heart disease as the leading cause of death in England and Wales in recent years — a direct consequence of population ageing. As more people survive to advanced old age, the prevalence of age-related neurological conditions increases. Dementia care is exceptionally expensive and labour-intensive, placing pressure both on the NHS and on the social care sector, which relies heavily on private providers and family carers.

Migration as the Growth Engine

With the birth rate at a record low and natural change contributing only modestly to population growth, net migration has become the dominant driver of UK population change. In 2022, natural change — births minus deaths — contributed approximately 60,000 people to population growth. Net migration in the year to June 2023 was estimated by the ONS at approximately 685,000. This means migration accounted for over 90% of all UK population growth in that period — a historically unprecedented situation.

What makes up net migration?

Net migration is not a single flow but the sum of many different categories of arrivals and departures. The largest categories of long-term arrivals in 2022–2023 included international students and their dependants — the single biggest category by visa type — followed by workers arriving on skilled worker visas, and humanitarian arrivals including Ukrainian nationals under the Homes for Ukraine scheme and British National (Overseas) visa holders from Hong Kong. EU migration, which dominated flows before Brexit, has diminished substantially but not disappeared. Emigration — British nationals and others leaving the UK — also contributes to the net figure.

Why does migration matter so much to the UK economy?

Net migration on this scale is not simply a demographic statistic — it has direct economic significance. The NHS is heavily dependent on internationally recruited staff: as of 2024, approximately 30% of NHS doctors and 20% of nurses were trained overseas. Social care — an already under-resourced sector — relies on migrant workers to fill approximately 150,000 vacancies. Sectors including construction, food processing, hospitality, and logistics are similarly dependent on migrant labour to meet demand that the domestic workforce alone cannot satisfy, given demographic constraints. Without sustained migration, labour shortages in these sectors would become acute, with consequences for public services, food security, and construction output — particularly for the government's housebuilding ambitions.

The tension: growth and pressure on services

High net migration creates a genuine policy tension. On the one hand, it sustains economic output, fills public sector roles, and contributes tax revenues that help fund public services. On the other hand, population growth driven by migration increases demand for housing — at a time when the UK is already experiencing a severe housing shortage — and puts additional pressure on schools, GP surgeries, hospitals, and transport networks. This tension sits at the heart of much of the political debate around migration policy in Britain.

An Ageing Population

Population ageing is perhaps the most consequential long-run demographic trend facing the United Kingdom. In 2023, approximately 12.7 million people — around 19% of the population — were aged 65 or over, according to ONS estimates. By 2050, if current trends continue, that proportion is projected to reach approximately 25%, meaning one in four people in the UK will be a pensioner. The growth in the very oldest age groups — those aged 80 and over — is even more rapid, as post-war baby boomers age into advanced old age.

The old age dependency ratio

The old age dependency ratio — the number of people aged 65 and over per 100 people of working age (16–64) — is a key measure of the fiscal burden of ageing. Currently, the UK ratio stands at approximately 28 retirees per 100 working-age people. ONS projections suggest this will rise to approximately 35 by 2040, meaning a smaller working-age population will be supporting a substantially larger retired population. This is the structural driver behind rising state pension costs, growing NHS demand, and the projected long-run deterioration in public finances.

State pension and the triple lock

The state pension is the UK's largest single welfare expenditure, costing approximately £120 billion per year in 2024/25. The triple lock guarantee — under which the pension rises by the highest of earnings growth, CPI inflation, or 2.5% — has ensured that pension values have increased substantially in real terms over the past decade. With an ageing population and the triple lock in place, state pension costs are projected to consume a growing share of GDP over coming decades. The OBR's Fiscal Sustainability Report projects that pension spending alone could rise from around 5% of GDP today to over 7% by 2070 under central assumptions.

Pressure on the NHS and social care

People aged over 65 use NHS services at approximately three times the rate of younger adults. An ageing population therefore drives a structural increase in NHS demand that goes beyond cyclical pressures. The number of people living with multiple long-term conditions — known as multimorbidity — is rising, and these individuals require complex, coordinated care that is more expensive to deliver. The social care sector, meanwhile, faces a crisis of capacity: approximately 150,000 vacancies were unfilled across the social care workforce in 2023, reflecting both low pay and difficult working conditions. As more people require residential or domiciliary care in old age, the sector's capacity challenges will intensify unless significant investment is made.

Future Population Projections

The ONS publishes periodic national population projections based on assumptions about future fertility, mortality, and migration. The 2021-based principal projection — the central scenario — suggests that the UK population will reach approximately 73.7 million by 2036 and potentially exceed 80 million by 2070 under high-migration assumptions. Under low-migration scenarios, growth slows substantially, and the population could begin to fall in the second half of the century if fertility does not recover.

Key variables in the projections

Three factors determine the trajectory of the UK population over coming decades. The first is fertility: if the TFR recovers toward 1.7 or 1.8 — as happened in the 2000s — natural population decline becomes less acute. If it continues to fall toward 1.2 or below, demographic decline becomes a more urgent structural challenge. The second is migration: immigration policy is now the principal lever governments can use to influence population size in the short to medium term. If net migration is reduced significantly through policy tightening — something successive governments have promised but struggled to deliver — population growth will slow and may eventually reverse. The third is mortality: further improvements in life expectancy will increase the size of the older population even without any change in birth rates or migration.

Economic implications of an ageing, slower-growing population

The OBR's long-run fiscal projections make sobering reading. In the absence of policy reform, age-related spending — pensions, NHS, and social care — is projected to rise from approximately 18% of GDP today to over 25% by the 2070s. Tax revenues, meanwhile, are unlikely to rise at the same pace if the working-age population grows more slowly. The result is a structural fiscal deterioration that would, over time, push the national debt to unsustainable levels.

Potential policy responses include raising the state pension age — already moving from 66 to 67 by 2028 under current legislation, with further increases to 68 under review — investing in preventive health to extend healthy life expectancy and reduce NHS demand, reforming the social care funding model to put it on a more sustainable footing, and maintaining skills-focused migration to fill gaps in the workforce. None of these responses is straightforward, and each involves difficult political trade-offs.

What this means for the UK in 2026

In 2026, the demographic pressures described in this article are not distant projections — they are already materialising. NHS waiting lists of over 7 million reflect, in part, an older and sicker population placing growing demand on a system built for a younger one. The housing crisis is partly a story of a growing population in a country that has not built enough homes to keep pace. The political debate about migration is inseparable from the demographic reality that, without it, critical parts of the public sector and economy could not function. The UK's population story is one of the central policy challenges of the coming decades.

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