Population | Key Topics

  • Mass migration is the major cause of our rapid population increase.
  • It is estimated that net migration plus births to foreign-born parents has accounted for 85% of UK population growth since 2000.
  • Under the official ‘high’ migration scenario the population is projected to rise by around 500,000 a year – the equivalent to a new city the size of Liverpool every year.
  • 75% of this increase will be down to future migrants and their children.

Recent Population Growth

1. Since 2000 the population of the UK has increased at a faster rate than any time in the previous 90 years. Unlike previous episodes of growth, the major reason for this increase has been the high level of immigration.

2. The population growth of a country is affected by the birth rate, the death rate and net migration (the difference between immigration and emigration). Immigration adds to the population both directly from the migrant themselves and indirectly by increasing the number of births in the country. In 2015, over a quarter (27.5%) of live births were to mothers born outside the UK, the highest level on record. This percentage has increased every year since 1990, when it was 11.6% (see here).

3. In 2001 the population of the UK was estimated to be 59.1 million with 4.9 million (8.3%) foreign born. By 2011 the population of the UK had increased by 4.1 million to 63.2 million with the foreign born population at 8 million (12.6%). In 2015, the population of the UK was estimated to be around 65 million.

4. It is estimated that net migration plus births to foreign-born parents has accounted for 85% of population growth between 2000 and 2014 (see here).

England is already highly overcrowded

5. Over 90% of international migrants to the UK go to England which now has a population density of 410 people per square km (see here). The population density of England is just lower than India and nearly twice that of Germany and 3.5 times that of France.

Future population Growth

6. If net migration continues at recent levels the UK will become ever more crowded. Projections of future population growth have to make assumptions about net migration, birth rates and mortality but, in the UK, net migration at recent levels is the largest driver of population growth. The total fertility rate (TFR) is the average number of children per woman implied by current trends. In the last forty years TFR has remained fairly stable, between 1.7 and 1.9. In 2015, the TFR decreased to 1.82 children per woman, from 1.83 in 2014. Among local authorities in England in 2015, City of London had the lowest TFR (1.00), Barking and Dagenham had the highest (2.42). The East of England was the English region with the highest TFR (1.92) (see here). A TFR of 2.1 is required to replace the population in the long run.

7. The UK population is ageing as the birth rate has fallen since the last century and as life expectancy increases. This means that the ratio of people of working age to people over retirement age is declining (given the working age limits of 16-64 although that upper limit is, of course, now obsolete). Some claim that, as a result, more working age migrants are needed to fund the cost of caring for people in their old age. While immigration can moderate population ageing, the effect is not strong and migration cannot solve population ageing since, obviously, migrants also grow old. They would need to be replaced by an ever-increasing flow of immigrants to have any continuing effect on the age structure of the UK. The result would be a substantial and continuing increase of the population, potentially without end.

8. The Office for National Statistics produces projections on different assumptions about net migration. If net migration were reduced to zero (that is, the numbers of people entering and leaving the country were the same) the population would rise gradually to 67.7million (from its current 65 million) in twenty-five years before gradually declining from the middle of the century.

9. In contrast, under the principal projection from the ONS with net migration at 185,000, the population is expected to increase by a total of 9.7 million over the next twenty-five years, passing the 70 million mark sometime in 2026 (see here).

10. If net migration continues at around recent levels, (net migration has averaged 250,000 in the last ten years) then the population is projected to rise by 500,000 a year and so reach 73 million in the next 15 years. This is the ONS ‘high’ migration scenario of 265,000 per year. This increase of nearly 8 million people is the equivalent of adding the combined population of Greater Manchester and the cities of Birmingham, Glasgow, Liverpool, Leicester, Leeds, Sheffield, Bradford, Nottingham, Portsmouth and Bristol. 75% of this increase would be from future migration and the children of those migrants.

11. The population growth would not stop there. It would continue to increase towards 80 million in 25 years and keep going upwards. These projections are illustrated below.

Figure 1.

Table 1: The impact of future net migration on the UK population

Projectionnet migration assumptionUK Population in 2039 (millions)Population increase (millions)% of increase down to future migration
Zero netZero67.73.10

Source: 2014 based Population Projections, Office for National Statistics.

12. The vast majority of population growth is projected to occur in England. Of the 9.7 million increase in the UK population projected by 2039 under the principal projection, 9 million, or 92.5% is due to take place in England which will present very significant problems for housing and public services in Table 2. 2014-Based Principal Projection; Increase of England Population as Percent of UK Increase.

UK Increase from 2014 (Millions)
England Increase from 2014 (Millions)
England Increase as % of UK Increase92.291.991.992.192.5


13. Such rapid population growth has severe impacts on the provision of public services such as school places. Similar strains will be placed on infrastructure like the transport network. Roads will have to be widened and new ones built to deal with the extra traffic while overcrowding on the railways will increase. Adequate housing will have to be built to accommodate all the extra people, either by making our urban areas more overcrowded or by building on green field sites with the loss of valuable amenities like beautiful countryside and productive farmland. Already, in recent years most additional heads of households have been born abroad.

Government Policy

14. No UK government has had a population policy but the present government does have a target of reducing net migration to the tens of thousands. This would significantly slow the rate of population increase.

Updated December 2016

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