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Naturalisation as a British Citizen: Concepts and Trends

18 Jul 2017

  1. Key Points
    • In 2016, just over 149,400 foreign nationals naturalised as British citizens. This is an increase on 2015 – which saw the lowest annual number since 2002 – but it is lower than the period between 2009 to 2013.
    • 8% of citizenship applications were rejected in 2016. The majority of refusals since 2002 have been because of failure to meet either the residence or the ‘good character’ requirements. English language requirements and the Life in the UK test account for a small percentage of rejected naturalisation applications but may deter additional potential applicants.
    • 52% of naturalisations in 2016 were of foreign nationals who have lived in the UK for the required five years, plus one additional year as a settled resident. Most of the other 48 per cent is split between spouses and civil partners of British citizens and minor children registering as citizens.
    • Amongst those naturalising in 2016 the largest groups in terms of previous citizenship were from India (16% of the 2016 total), Pakistan (11%), Nigeria (7%), and South Africa (3%). Only 12% of grants were to EU nationals, though applications from EU nationals were at their highest.
  1. Understanding the Evidence

    Naturalisation is the acquisition of British citizenship by someone who held (or continues to hold) foreign citizenship. There are several routes to naturalisation. Adults may qualify for British citizenship through at least five years of residence in the UK, or through marriage to a British citizen (with three years’ residence in the UK as a spouse or civil partner). Naturalising citizens must also meet requirements of ‘good character’, the ability to communicate in English (or Welsh or Scottish Gaelic), and ‘knowledge of life in the UK’ (as assessed by a Life in the UK test, also required for those applying for settlement). Children may qualify for either automatic or discretionary “registration” as British citizens depending on the country of their birth and nationalities of their parents. Home Office administrative data counts citizenship grants of each of these types. Though registrations are not technically naturalisations, at least in Home Office classifications, they are included with naturalisations in this briefing.

    Home Office data includes information on refusals of citizenship applications, including those refused because of a failure to demonstrate language proficiency or knowledge of life in the UK.

    Note: Data prior to 2005 include grants of the “right of abode“ (a form of permission to live permanently in the UK) as a Commonwealth citizen; since 2005, this category, small in number, is recorded separately from naturalisations to British citizenship. Note that all Home Office statistics in this briefing that are greater than 1,000 are rounded to the nearest 100. Figures in tables and charts are not rounded.

Citizenship grants per year more than doubled from 2000 to 2013 but fell in 2015 and 2016

In 2016, 149,400 foreign nationals naturalised as British citizens. This is down almost 30% from 2013 when citizenship grants reached almost 208,000, the largest annual number since records began in 1962 – but is still an increase on 2015’s total of 118,000 or 2014’s 125,000.

According to the Home Office (2014), the 2013 peak in citizenship grants followed an increase in applications prior to changes to language requirements, while lower numbers of grants in 2014 were in part due to the shifting of resources from UK Visas and Immigration (UKVI) to HM Passport Office. The increase in number of decisions made on citizenship applications in 2016 contrasted with a fall in the number of applications submitted (applications fell by about 19,900 or 13% from 2015 to 2016).

Lower numbers of citizenship applications in recent years are also consistent with recent decreases in grants of settlement/indefinite leave to remain (from 241,200 in 2010 to 104,100 in 2014 and 89,900 in 2015), which will have reduced the pool of people newly eligible to apply for citizenship.

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The number of accepted and rejected citizenship applications is affected by policy and administrative changes

Recently refusal rates increased up to 8.6% in 2015 and 8.2% in 2016, from lows of 3.4% in 2012 and 2013. In the past the refusal rate was also higher, with 9.3% as recently as 2005, and at least 10% for most of the 1990s (see Figure 1). The increased acceptance rates up to 2010 were partially the result of new application checking services that catch incomplete or inadequate applications before they are filed (Home Office 2010: 10). The Home Office (2016) attributes the recent decline in the grant rate to the introduction of ‘enhanced checks on cases requiring higher levels of assurance’ in April 2015

Figure 1

Changes to law and administrative procedures have resulted in notable spikes in naturalisation. In chronological order: 1974-1975 saw an increase in grants to Pakistanis following the Pakistan Act of 1973 (which created a temporary window for Pakistani nationals to register as Citizens of the United Kingdom and Colonies, after which naturalisation would be required as for non-commonwealth nationals). Next, the increase in 1989 comes from the opening of a new application processing centre in Liverpool, increasing administrative capacity. Finally, increases in grants through registration since 2003 may reflect new provisions in the Nationality, Immigration and Asylum Act 2002 (Home Office 2010: Table A notes).

The introduction of the Life in the UK test and more stringent English language requirements in 2004 does not seem to have changed the increasing trend in naturalisations until 2013. It is possible that there would have been more naturalisations without these new requirements and tests (including the fees required to prepare for and take them). The language and knowledge requirements would seem to pose a greater burden on citizens of poorer, less educated and non-English-speaking countries (Ryan 2008), and may have deterred their applications.

In the first quarter of 2017, a record 9,500 applications for naturalisation were made by EU nationals, slightly over three times as many as the quarterly average applications from EU nationals between 2009 and 2016. This increase was higher amongst those from EU14 countries, whose applications in Q1 2017 more than quadrupled (4,800) as compared with the first quarter of 2016 (1,100). Amongst EU2 and EU8 nationals, there were also a higher number of applications in Q1 2017, with 1,500 EU2 and 3,100 EU8 applications.

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Residency, marriage, and children are the three main grounds for citizenship grants

British citizenship grants are divided among three main categories: migrants fulfilling the five-year residency requirement, spouses and civil partners of British citizens, and underage children being registered as citizens. Figure 2 shows about half of grants overall come from residency requirements (52% in 2016). The two family routes account for slightly less than half combined (marriage/civil partnership made up 18% in 2016; children made up 25% in 2016). The remaining 5% were “other” bases for citizenship, including, for example, transfers from British overseas territories citizenship to full citizenship status. The Home Office (2016) notes that grants on ‘Other grounds’ have almost doubled between 2015 and 2016 from 4,100 to 8,100, because of increases in decisions relating to persons who had spent the first 10 years of their life in the UK, and persons born to a British father before July 2006, where their parents were unmarried at the time of their birth.

Figure 2

Each of the main pathways to naturalisation (residence, marriage, and registration of minor children) grew in numbers from 2000 to 2013, subsequently fell and now seem to be rising in 2016.

Residence-related grants increased from 35,000 (43% of all grants) in 2000 to 113,300 (54%) in 2013, before falling to 60,800 (51%) in 2015 and climbing to 77,600 (52%) in 2016. Naturalisation through marriage almost doubled throughout the 2000s, from 27,400 (33%) in 2000 to 52,600 (26%) in 2009 but then decreased to 26,800 (18%) in 2016. Grants to minor children increased from 19,200 (23%) in 2000 to a peak of 48,700 (25%) in 2010 and stood at 36,900 (25%) in 2016. “Other” categories have fluctuated between 1% and 5%.

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88% of grants of citizenship in 2016 were to non-EU nationals

The largest groups of newly naturalised UK citizens in 2016 had prior citizenship from India, Pakistan, Nigeria, and South Africa (see Table 1). Asian nations contributed the most to growth in naturalisations over time (see Figure 3). African nationals also contributed heavily to the growth in naturalisations in the 2000s. Nigeria, South Africa, Zimbabwe, and Ghana ranked among the top 10 prior nationalities of new UK citizens in 2016.

Nationals of EU countries made up only 12% of citizenship grants in 2016, despite their significant contribution to overall UK migration over the past decade. The number of grants to EU nationals increased by around 4,200 to 17,200 in 2016, from 13,000 in 2015.

Migrants from Asia and the Middle East have seen a decline in the numbers of citizenship grants issued since 2013 and 2012 respectively, but Asia is still the predominant source – with 66,700 grants in 2016. The EU has been growing as a source of naturalised British citizens. Citizens of countries that joined the EU in 2004 are a small share of total grants (5% in 2016), but increased from 2009 onwards as they began to become eligible to naturalise. The number of grants to nationals of accession (A8) countries rose from 869 in 2009 to slightly fewer than 7,000 in 2016.

Grants of citizenship to nationals of North and South American countries averaged 21,100 annually between 1983 and 1989 before dropping to 4,900 annually in the 1990s and 10,800 annually from 2000 to 2016.

Figure 3

Table 1 – Top ten nationalities as share of total, 2015

Country of previous nationalityNumberShare of total
South Africa5,064
United States

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The demographic profile of naturalising citizens leans toward the young and female, as shown in Figure 4. In 2016, 52% of adults receiving citizenship were female. Including children, the distribution was 40% adult women, 36% adult men, and 25% children.

Figure 4

By age group, adults aged 25-44 comprised the majority of naturalising citizens (55% of the total). Only 13% were 45 and older; 25% were children aged under 16. Women outnumbered men primarily among young adults (16-24 and 25-34 age groups). Men outnumbered women in the 35-54 age groups.

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Legal barriers, language and integration, and poverty in origin country affect naturalisation rates

Naturalisation reflects both legal requirements and a personal choice. One would expect that naturalisation is more likely when there are few legal barriers, when naturalisation brings greater benefits, and when naturalising does not entail giving up much of value, such as a previous citizenship.

Each of these aspects of the determinants of naturalisation has been researched:

First, naturalisation rates are lower in nations that impose more legal requirements for acquiring citizenship. Traditionally, nations have been categorized as following one of two logics of citizenship: jus soli (literally ‘right of soil’) where citizenship comes from being born in the country, and jus sanguinis (literally ‘right of blood’) where citizenship comes from parents’ citizenship and in-country birth does not confer citizenship. Contemporary citizenship law in many nations blends the two logics in varying proportions.

Overall, British citizenship law is more open to naturalisation than traditional jus sanguinis nations such as Germany. Although the UK may be viewed as the original jus soli country it is now less open than other traditional jus soli nations such as the USA and Canada.

In a comprehensive comparative study, Janoski (2010) identifies as many as 12 requirements that countries may impose; many of which are now included in British citizenship law (Sawyer 2009). These include requirements of good conduct, language skills, efforts toward cultural integration (measured in the form of the Life in the UK test), years of residency, and navigation of complex and expensive application procedures.

From 2002 to 2016, the majority of refusals to grant citizenship were because of a failure to meet either the ‘good character’ requirement or the residence requirement. The ‘good character’ requirement accounts for an increasing number of rejected applications for naturalisation, rising to 44% of all refusals in 2016 (from 10% to 13% in the years immediately preceding legal changes to this requirement in 2008). Failure to demonstrate language proficiency or knowledge of life in the UK comprised 5% of refusals (673 people), as shown in Table 2. Refusals due to delays in replying to enquiries from UKVI risen in recent years– from 423 in 2013 (6%) to 1,698 in 2016 (13%).

Table 2 – Reasons for refusal, naturalisation applications, 2015

Reasons for refusal2014Share2015Share2016
Not of good character109519%4,524
Residence 122421%2,82527%2,632
Delay in replying to enquiries from UKVI123422%1,254
Parent not a British citizen5109%7497%931
Insufficient Knowledge of English and KOL4899%5315%673
Incomplete applications72813%2542%128
Oath not taken in time60%140%9
Total refusals570910,646

British citizenship law also does not require renunciation of prior citizenships in order to naturalise. (Law in the sending nation is relevant here as well. Zimbabwe, for example, has not permitted dual citizenship, probably lowering Zimbabwean naturalisation rates in the UK.)

Research on the determinants of naturalisation and the ways in which costs and benefits to individuals influence their decision to naturalise or not—has been conducted mainly in North America rather than the UK (Bloemraad, 2006). A recent European study of naturalisation identifies nine factors associated with higher naturalisation rates. For individuals, naturalisation is more likely for migrants who speak the destination country’s language, who have a parent born in the destination country and who have resided longer within it. In addition, people from poor or unstable countries or from former colonies of the destination country are more likely to naturalise. Among the second generation (children of migrants), naturalisation seems to be less common among Muslims than among others. Countries where citizenship law is relatively permissive and where net migration rates are low, the study finds tends to have higher naturalisation rates (Dronkers and Vink 2010).

For migrants to the UK, the basis for initial entry also partially determines the likelihood of naturalising. Migrants who arrive in the UK with family visas or as skilled or highly skilled workers (pre-PBS equivalents of Tier 1 and Tier 2 visas) are more likely to naturalise than those with student visas or temporary work visas. Students and temporary workers do not accumulate time toward fulfilling residency requirements unless they change their status to a category that is eligible for naturalisation, for instance through marriage to a British citizen or by obtaining a visa based on longer term work.

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Evidence gaps and limitations

Administrative data on naturalisations provide complete and presumably accurate counts of grants of citizenship by category of eligibility (residence, family, or registration). The Home Office compiles figures from a database in which caseworkers enter information about each applicant for naturalisation. Published statistics are generated from this database.
A minority of applications for citizenship are refused; these refusals are also tracked in administrative data, including the reason for rejection. Some of these simply fail to meet straightforward requirements such as length of residence; others reflect more discretionary judgements, such as the ‘good character’ requirement. In 2008, the Home Office changed its interpretation of the good character clause, making it difficult for people with past criminal convictions to attain citizenship.

Since naturalisation represents a change in the relationship between an individual and the government, trends in naturalisation reflect not only trends in migration but also changes in government policy and administrative practice. Several cases are discussed in this briefing in which a change in policy or administrative practice had noticeable effects on the number of naturalising citizens in a given year or period. However, a crucial limitation is that administrative data on applications, grants and refusals cannot show the number of potential citizenship applications that might be deterred by added requirements. These include the 2004 and 2005 changes requiring a higher standard of English language proficiency and a demonstration of knowledge of life in the UK, and the fees accompanying applications for settlement, naturalisation, and the Life in the UK test. Some research attempts to estimate this deterrent effect (Ryan 2008), but this requires estimations based on assumptions and cannot be counted straightforwardly in the data. Still, given that some individuals may not feel capable of passing the required language and knowledge tests, and others may have difficulty affording the fees (particularly families, since fees apply to each individual), this deterrence could be an important impact of these policies.


  • Bloemraad, Irene. “Becoming a Citizen in the United States and Canada: Structured Mobilization and Immigrant Political Incorporation.” Social Forces 85, no. 2 (2006): 667-695.
  • Dronkers, Jaap, and Maarten Vink. “Explaining Immigrant Citizenship Status: First and Second Generation Immigrants in Fifteen European States.” MPRA Paper No. 26198, Maastricht Research School of Economics of Technology and Organization (METEOR), Maastricht University, 2010. Accessed 9 November 2010.
  • Home Office. “British Citizenship Statistics, United Kingdom, 2009.” Statistical Bulletin, Home Office, London, 2010.
  • Home Office. “Immigration Statistics, October to December 2014.” London: Home Office, 2015.
  • Home Office. “User Guide to Home Office Immigration Statistics”, updated May 26, 2016.
  • Janoski, Thomas. The Ironies of Citizenship: Naturalization and Integration in Industrialized Countries. Cambridge: Cambridge University Press, 2010.
  • Ryan, Bernard. “Integration Requirements: A New Model in Migration Law.” Journal of Immigration Asylum and Nationality Law 22, no. 4 (2008): 303-316.
  • Sawyer, Caroline. “EUDO Citizenship Observatory Country Report: United Kingdom.” Florence: European University Institute, 2009. Accessed 9 November 2010.

Further Reading

  • Brubaker, R. Citizenship and Nationhood in France and Germany. Cambridge, MA: Harvard University Press, 1992.
  • Yang, P. Q. “Explaining Immigrant Naturalization.” International Migration Review 28, no. 3 (1994): 449-477.

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