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Net migration to the UK

26 Jul 2019

This briefing provides an overview of net migration to the UK – defined as the difference between immigration and emigration of people moving for at least a year.

  1. Key Points
    • Net migration to the UK, the difference between immigration and emigration, was estimated to be 258,000 in 2018. This is down from a peak of 336,000 in the year ending June 2016, just before the EU referendum
    • Net migration of EU citizens rose substantially from 2012 onwards and fell sharply after the EU referendum
    • Estimated non-EU net migration averaged around 196,000 from 2009 to 2018, but this estimate may be inaccurate and it is possible that the true figure is lower
    • Work and study are the most common reasons for immigration to the UK, but their contribution to net migration cannot currently be accurately calculated
  1. Understanding the Evidence

    The analysis in this briefing is based on data from the Office for National Statistics (ONS) estimates of Long-Term International Migration (LTIM). The primary data source for the LTIM estimates is the International Passenger Survey (IPS), which is based on respondents’ stated intention to come to or leave the UK for at least one year. But LTIM estimates also include adjustments based on data from other sources, such as Home Office data on asylum seekers, the Labour Force Survey, and the Northern Ireland Statistics and Research Agency international migration estimates. To correctly interpret LTIM data, it is important to recognise its underlying definitions and limitations. ONS uses the UN’s international standard definition of a long-term international migrant to produce LTIM estimates: a person who moves to another country for at least one year (see ‘Evidence Gaps and Limitations’ below for further discussion). This excludes, for example, tourism or short-term business related travel.

    There is uncertainty about the accuracy of some of the components of the IPS and LTIM estimates. In particular, is has become clear that the emigration of non-EU students is not being correctly captured in the IPS survey, though it is not yet clear to what extent data problems also exist for other categories of migrant (Office for National Statistics, 2018a). Fluctuations in IPS figures – which have significant margins of error – are not always visible in other data sources such as visa issuances. ONS has frequently said that it believes the IPS – which is commonly used in policy debates to scrutinise specific subcategories of migration such as non-EU students or EU workers – has been “stretched beyond its original purpose” (Office for National Statistics, 2019a). It has also cautioned against reading too much into year-on-year variations in specific components of net migration, because sampling error means that short-term changes in the estimates may represent statistical noise rather than a real trend.

    Note that some of the LTIM estimates for 2001 to 2011 have been revised following problems uncovered for that time period, while other estimates have not. In April 2014, ONS published its report on the ‘Quality of Long-Term International Migration estimates from 2001 to 2011’, in which they revised the numbers of total net migration for the years 2001 to 2011. Based on the revision, total net migration between 2001 and 2011 had previously been underestimated by 346,000. There is evidence that this underestimation was predominantly driven by an undercount of migration from the EU-8 eastern European countries. However, revised numbers of immigration and emigration as well as breakdowns by citizenship or reason for migration are not currently available. As a result, estimates relating to any breakdown of immigration, emigration, or different reasons for migrating will not match overall net migration.

    This briefing uses the term EU-15 to describe EU countries other than the UK that were members of the EU before enlargement in 2004. EU-8 refers to the eight east European countries that joined the European Union in May 2004: Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Slovakia, Slovenia. EU-2 refers to the countries that joined in 2007: Romania and Bulgaria.

Net migration to the UK, the difference between immigration and emigration, was 258,000 in 2018, down from a peak of 336,000 in the year ending June 2016

The headline net migration statistic includes people of all citizenships, including British citizens leaving the country or coming from abroad. As shown in Figure 1, net migration rose from -13,000 in 1992 to 163,000 in 1999. In the mid-2000s there was a significant increase in net migration that coincided with the 2004 EU enlargement.

Net migration fell between 2010 and 2012, from 256,000 to 177,000. This period coincided with several policy measures designed to restrict study, work and family migration, as part of the Conservative Party’s goal to reduce net migration to the “tens of thousands”. The lowest estimate of net migration during this period was 154,000 in the year ending September 2012.

Levels started to increase again from 2013 onwards. This increase took place at a time when the UK economy was starting to recover from the economic crisis, but some of the key origin countries of migrants to the UK (particularly in southern Europe) were still experiencing high unemployment.

The highest level of net migration on record is 336,000, reached in mid-2015 and again in the year ending June 2016, just before the EU referendum. In the year after the referendum (the year ending June 2017), net migration recorded its largest ever single-year fall, although part of this decrease was driven by a statistical anomaly in the measurement of non-EU students (Office for National Statistics, 2018a). The provisional estimate of net migration in 2018 was 258,000.

Figure 1


ONS also produces estimates of long-term international migration at the local-authority level data on migration, which can be found in the Migration Observatory’s Local Data Guide.

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Net migration of EU citizens rose substantially from 2012 onwards but fell sharply after the June 2016 EU referendum

Figure 2 shows net migration for EU and non-EU citizens, as well as total net migration, which includes British citizens.

Before 2004, net migration of EU citizens fluctuated but remained below 35,000 each year. It saw a sharp increase after EU enlargement, from 2004 to 2007, although the figures for this period are underestimates due to a problem with the measurement of net migration at this time (see ‘Understanding the Evidence’ above). EU net migration was estimated at 127,000 in 2007, then fell around the time of the financial crisis, from 2008 to 2012. A second increase in EU net migration took place from 2013 onwards, peaking at 189,000 in the year ending June 2016. EU net migration then fell sharply following the EU referendum.

The decline in EU net migration between the year ending June 2016 and the year ending December 2018 was spread across all of the three main EU origin groups – EU-15, EU-8 and EU-2. During this period, net migration fell from 84,000 to 47,000 for EU-15 citizens, from 42,000 to -10,000 for EU-8 citizens, and from 62,000 to 33,000 for EU-2 citizens. These estimates are subject to significant margins of error and this means that the negative net migration estimate for EU-8 citizens was not statistically different from zero. 

Figure 2


Adding together EU and non-EU figures does not lead to total net migration, because total net migration includes British citizens. British citizens are the only group with continuous net emigration since 1991 (i.e. negative net migration). Peaks in British net emigration occurred in 2004 (104,000) and 2006 (124,000). In 2018, provisional estimates suggest that there were 48,000 more British citizens moving abroad than coming to live in the UK.

For more information on EU migration in the UK, see the Migration Observatory briefing, EU Migration to and From the UK.

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Estimated non-EU net migration averaged around 196,000 from 2009 to 2018, but this estimate may be inaccurate

In 2018, estimated net migration of non-EU citizens was 232,000. This figure has fluctuated over time (Figure 2, above), averaging 196,000 over the ten-year period from 2009 to 2018.

Although this suggests that the net migration of non-EU citizens in 2018 was roughly three times net migration of EU citizens – despite policies introduced from 2010 onwards to restrict non-EU migration – there is reason to be cautious about making this comparison. Other data sources suggest that the net migration of non-EU citizens may be lower than the headline IPS figures suggest.

An ONS report published in July 2018 presented preliminary analysis of a comparison of the IPS figures, which are used to calculate net migration, with Home Office data on visas issued and entries or exits from the UK. It found that while estimated immigration inflows in the two sources were similar, the IPS showed much less emigration than the Home Office data (Office for National Statistics, 2018a). The gap was driven primarily but not exclusively by non-EU students, whose emigration appears to be significantly undercounted in the net migration figures.

Similarly, a different source of data on migrants in the UK – the Annual Population Survey (APS) – suggests that the non-EU born population of the UK has not increased as much as one would expect if net migration had really averaged 196,000 per year for ten years (for a full discussion see Office for National Statistics, 2019b). The non-EU born population of the UK increased by only an estimated 937,000 from 2009 to 2018 – an average of 93,700 per year (Office for National Statistics, 2019b). The trend of EU citizens is the reverse, with the APS population data suggesting significantly larger increases than the net migration data. ONS is currently investigating potential reasons for this discrepancy (ibid).

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Work and study are the most common reasons for immigration to the UK, but their contribution to net migration cannot currently be accurately calculated

As people often move for a variety of reasons, it can be difficult to categorise migrants based on their reasons for migrating to the UK (for a discussion of mixed migration motivations see our primer Mixed Migration: Policy Challenges). For example, someone might move to the UK to join their spouse, work part-time and also study. It is therefore important to keep in mind that while ONS records the categories discussed below as mutually exclusive, this will not always be the case in practice.

In 2018, an estimated 216,000 people or 36% of long-term migrants moved to the UK for work-related reasons (including British citizens) (Figure 3). These people either had a definite job – 26% of all immigrants – or came to look for a job – 10% of all long-term arrivals. The sharp decline in work-related migration from 2016 to 2018 was a result of a fall in EU migration after the 2016 referendum. For more information on work-related migration, see the Migration Observatory briefing, Work Visas and Migrant Workers in the UK.

In 2018, 35% of long-term migrants said they were coming to the UK for study. Study migration is driven by non-EU citizens, while work migrants are more likely to be EU citizens. For more information about non-EU students, see the Migration Observatory briefing, Non-European Student Migration to the UK.

The number of people who came to accompany or join a family member was substantially lower, at an estimated 51,000 people, or 8% of total long-term immigration. For more information about family migration, see the Migration Observatory briefing, Non-EU Family Migration to the UK.

Figure 3


Since 2012, ONS has collected data on emigration from the UK by initial reason for migration. In theory, this should make it possible to understand which categories of migration – work, family, study, or other reasons – have contributed most to net migration.

However, as noted above, estimates of the number of non-EU students who subsequently emigrate are now recognised to be inaccurate (Office for National Statistics, 2018a). It is not yet clear to what extent this means that other categories of net migration (e.g. people arriving for work or family) are also inaccurate.

These problems with the data make it important not to draw strong policy conclusions from the net migration figures on specific routes. It also means that there is currently no robust way to remove international students from any government net migration target for net migration levels, as some stakeholders have proposed—at least if such a target continues to be based on IPS estimates.

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Evidence Gaps and Limitations

ONS is currently revising the way it produces migration statistics, and from 2020 is planning to make greater use of administrative data such as visa records, exit checks, tax records and NHS data. This may mean that the IPS, on which the net migration figures in this briefing are based, has a diminished role in the UK’s migration statistics landscape in the future.  This programme of work aims to improve the understanding of why IPS figures are not always consistent with other sources, such as the Annual Population Survey or visa data (Office for National Statistics, 2019b). This is a complex exercise, however, because different sources of data are collected in different ways and often measure different things. As a result, there are often several plausible explanations for discrepancies between data sources and it is not straightforward to determine which is responsible.

In the meantime, it is not sensible to use the IPS and net migration figures for detailed scrutiny of different categories of migration and their contribution to net migration overall. Using these data to draw policy conclusions about how to treat different types of migration (for example, to draw up a plan for reducing net migration to a given level) would be misleading.

It is also important to note that the IPS estimates of immigration and immigration are not designed to account for short-term migration. This is one reason why immigration figures from the IPS are, for some nationalities, smaller than the number of National Insurance Number registrations.

The International Passenger Survey asks individuals about their intended length of stay in the UK and abroad. People are classified as ‘long-term migrants’ if they state that they intend to move for 12 months or longer. However, migrants’ plans for the future, such as the intention to stay in the UK for a year or more, may or may not be realised. To address this, ONS adjusts the data for ‘visitor switchers’ –  those whose original intention was to stay for less than one year but who subsequently stay longer – and for ‘migrant switchers’ – those who intended to stay for a year or more but left within a year). However, making the adjustment is methodologically challenging, and with currently available data sources it is not possible to be certain about/of how much switching is actually taking place and what the implications are of this for the overall net migration figures (Office for National Statistics, 2018).

Thanks to Ann Singleton for helpful comments and suggestions on an earlier draft, and to Peter Walsh for help updating the briefing in 2019.


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