8 November, 2023
1. Britain's population growth is nowadays entirely due to immigration. If net migration were to continue at the present record level of 606,000 a year, Britain’s population would rise to between 83-87 million by 2046. This would represent an increase of more than 15 million in Britain’s population – equivalent to fifteen new cities the size of Birmingham. This paper provides a description of what this would require in terms of new schools, hospitals, roads, bus lanes, colleges and police stations. Such mass immigration would place an intolerable strain on public services, especially health, transport and education. Table 1 provides a summary of the new infrastructure required. Of course, if net migration was to be held to four or five hundred the requirements for infrastructure would be proportionately less. There Is a strong case for an annual limit on net migration of about 100,000 a year.
Table 1: Infrastructure required to accommodate fifteen new Birminghams (2023) 
|Further education colleges||165|
2. According to Professor George Borjas of Harvard University, there are many “extravagant claims” that mass immigration increases the wealth of nations by the tens of billions of pounds. We are told that we need immigration to grow the economy, and that the more there is, the faster it will grow. As one political commentator recently put it: “Newcomers are a net benefit to a modern economy and should be welcomed accordingly.”
3. These claims are often accepted uncritically. Yet most serious academic attempts to identify such benefits have found that, at best, they are marginal. A larger population will certainly make the economy bigger, but it will not raise living standards unless it makes GDP (the quantity of goods and services) grow more rapidly than the population. What matters to the existing population is not GDP for its own sake, but GDP per head. Internationally, there is no evidence over the last century that countries with faster population growth have achieved faster income or productivity growth.
4. Economic benefits from immigration unquestionably exist. But, beyond a certain point, the benefits do not increase in proportion to the numbers settling here, whereas the problems (and costs) do. In a densely populated city like London, for example, rapid population growth puts immense strain on public services, roads and transport, while increasing the cost of land and housing. The British taxpayer will often have to bear the cost: either through higher taxes or hidden subsidies such as those to make accommodation more affordable for key workers.
5. Furthermore large-scale immigration places increasing pressure on the pre-existing stock of infrastructure and land, thus reducing productivity and living standards unless costly new investments; these in turn choke-off other productive investment.
6. In general, smaller countries can thrive in a world with free trade. Many of the countries with the highest incomes per head have small populations – countries like Luxembourg, Singapore, Denmark and Norway. In that sense, Britain does not ‘need’ large-scale immigration. It has a population of 67 million, and considerable reserves of unused labour. High migration will increase Britain’s aggregate GDP, but this has little to do with individual welfare where per capita GDP is the relevant measure.
7. Should the level of net migration be allowed to continue, we will have to build around 6,675 new schools, 2,640 new surgeries, 135 hospitals, 75 universities, 75 police stations and 165 further education colleges by 2046. Expansion of infrastructure on such a scale would be both difficult and costly to implement, but the pressure on public services would become too severe to ignore.
8. To arrive at these estimates we have taken local authority data from Birmingham City Council and multiplied it by fifteen. However, these projections do not account for variations in geography and future settlement patterns, which cannot be forecast accurately in advance. Nevertheless, these figures provide a snapshot of the infrastructural challenges that the UK government would face should the level of net migration continue at the record level of 606,000.
9. Given the demands on infrastructure, it is not surprising that data from 32 OECD countries show no statistically significant association between productivity and population growth. In parts of England there is already intense competition for primary school places. Moreover, new residents signing up with their local GP in areas where immigration is high will exacerbate longer waiting times for GP appointments and treatments. To illustrate this point, Table 2 provides a breakdown of the thousands of schools that would be needed for fifteen new Birminghams:
Table 2: Schools needed for fifteen new Birminghams (2023)
10. Some argue for making the investments early so that new infrastructure becomes available at the time it is needed. This reflects a belief that immigration pressures can be handled by building more homes, schools, hospitals, roads, rail networks and airports. Unfortunately, the changes required to accommodate a rapidly growing population may be both difficult and costly to implement, even when problems have become too severe to ignore. As Professor Robert Rowthorn has noted: “Suitable land may not be available except at great material or environmental cost. Re-engineering existing cities to accommodate the additional population may be very costly, and expansion into the surrounding countryside may be resisted by local people.”
11. In addition to the impact on schools and hospitals, there is also the impact of immigration on roads and transport systems. In 2022, the average London driver lost £1,377 due to congestion, while drivers across the country missed out on £707. According to the INRIX traffic scorecard, Birmingham is the fourth most congested city in the UK, with an average of 73 “hours lost”:
Table 3: INRIX traffic scorecard, UK (2022)
|Impact rank (UK)||Urban area||Hours lost||Change from 2021||Change from 2019||Last mile speed|
12. Should the level of net migration be allowed to continue until at about 600,000 a year until 2046, Britain will have to build around 7,785 new roads and 2,235 bus lanes. Diseconomies of congestion will occur when demand for road travel exceeds the supply of roads. According to INRIX, “negative externalities like freight delay, inflationary pressure and environmental impact are generally exacerbated due to traffic congestion.”
13. In terms of population size, large-scale immigration may have benefited sparsely populated countries when they needed a certain size of population to develop their resources and achieve economies of scale. However, the reverse is the case in a densely populated country like Britain: current levels of migration generate diseconomies of congestion and increase the cost of land and infrastructure. Rapid population growth means that some other investment that would otherwise occur will tend to be ‘crowded out’ to make way for the infrastructure needs of the increased population.
14. A serious downside to large-scale immigration is its impact on population growth. As the population increases, the UK economy may receive some benefit from a larger talent pool and, perhaps, greater specialisation. However, much of the current massive inflow is relatively low skilled and any resulting benefits must be weighed against the future costs that a larger population will impose on land, housing, services and infrastructure. This paper demonstrates that mass immigration to Britain would place intolerable pressures on public services, especially health, transport and education. Even at lower net migration of 4-500,000 per year there would be severe pressure on infrastructure. The way forward, therefore, is to establish an annual limit on net migration of about 100,000 a year and stick to it.