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Naturalisation as a British Citizen: Concepts and Trends

08 Aug 2016

This briefing gives details about how many foreign citizens acquire British citizenship every year, their demographic characteristics, and the various bases for their grants of British citizenship.

  1. Key Points
    • In 2015, just under 118,100 foreign citizens naturalised as British citizens. This was the lowest annual number since 2002, following a period of higher naturalizations by recent historical standards from 2009 to 2013.
    • 9% of citizenship applications were rejected in 2015. 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.
    • 51% of naturalisations in 2015 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 49 per cent is split between spouses and civil partners of British citizens and minor children registering as citizens.
    • Among British citizens naturalising in 2015 the largest groups by citizenship were from India (16% of the 2015 total), Pakistan (11%), Nigeria (7%), and South Africa (4%).  Only 11% of grants were to EU nationals.
  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). In addition to residency requirements, naturalising citizens must meet requirements of ‘good character’, 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 include 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 national; 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 considerably in 2014 and 2015

In 2015, 118,100 foreign citizens naturalised as British citizens. This is down more than 40% from 2013, when citizenship grants reached almost 208,000, the largest annual number since records began in 1962. From 2009 to 2013, citizenship grants averaged 195,800 per year.

According to the Home Office (2014), the 2013 peak in citizenship grants followed an increase in applications in advance of changes to language requirements, while lower numbers of grants in 2014 were at least in part due to the shifting of resources from UK Visas and Immigration to HM Passport Office. The number of decisions made on citizenship applications in 2015 did not increase in line with an increase in the number of applications submitted (applications increased by about 23,700 or 18% from 2014 to 2015), suggesting that the declining trend in citizenship grants may end in 2016 as these applications are processed.

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 129,800 in 2012 and 154,700 in 2013), 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

The acceptance rate for naturalisation applications was increasing until 2013, when 3.4% of applications ended in refusal or withdrawal. This was down from 3.9% in 2010, 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 at least partially the result of new application checking services that catch incomplete or inadequate applications before they are filed (Home Office 2010: 10). In 2014, 4.7% of applications were refused rising to 8.6% in 2015. According to the Home Office (2016), this decline in the grant rate can be attributed to the introduction of ‘enhanced checks on cases requiring higher levels of assurance’ in April 2015.

Figure 1

The trend in naturalisations has several notable spikes that can be explained as the result of changes to law or administrative procedures. 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 (including not only the newly-required knowledge and skill tests but also the fees required to prepare for and take them). Further, the language and knowledge requirements would seem to pose a greater burden on nationals of poorer, less educated and non-English-speaking countries (Ryan 2008), and may have deterred applications among nationals of such countries.

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

As noted above, 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. As seen in Figure 2, about half of grants overall come from residency requirements (51% in 2015). The two family routes (marriage/civil partnership and children) account for slightly less than half combined (marriage/civil partnership made up 21% in 2015; children made up 24% in 2015). The remaining 4% were “other” bases for citizenship, including, for example, transfers from British overseas territories citizenship to full citizenship status.

Figure 2

Each of the main pathways to naturalisation (residence, marriage, and registration of minor children) grew in numbers from 2000 to 2013 albeit with a temporary decrease in 2008. The decline in citizenship grants in 2014 also took place across all of three main categories.

Residence-related grants increased the most over the 2000s, both in number and in percentage terms. Grants from residence increased from 35,000 in 2000 to 113,300 in 2013, before falling to 62,500 in 2014 and 60,800 in 2015. Naturalisation through marriage almost doubled in the decade of the 2000s, from 27,400 in 2000 to 52,600 in 2009 but then decreased to 24,400 in 2015. Grants to minor children increased from 19,200 in 2000 to a peak of 48,600 in 2010, and stood at 28,700 in 2015. Since 2000 residence-related grants have grown from 43% of naturalisations in 2000 to 51% in 2015, while marriage-based grants declined from 33% to 20% in the same period. Minor children registrations constituted 23% in 2000 and 24% in 2015. “Other” categories fluctuated between 1% and 5%.

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89% of grants of citizenship in 2015 were to non-EU nationals

The largest groups of newly naturalised UK citizens in 2015 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 2015.

Nationals of EU countries made up only 11% of citizenship grants in 2015, despite their significant contribution to overall UK migration over the past decade. Data on naturalisations of EU citizens for 2016 – before and after the UK voted to leave the European Union – will become available in May 2017.

Europe and the Middle East grew as sources of naturalising British citizens until 2013, while only the Americas declined as a source region for naturalisations during this period. Naturalisations among citizens of countries that joined the EU in 2004 are a small share of total grants of citizenship (5% in 2015), but increased sharply from 2009 onwards as people arriving in the mid-2000s began to be eligible to naturalise. The number of citizens of accession (A8) countries rose from 869 in 2009 to just under 8,300 in 2013. Since then it has dropped to 5,800 in 2015.

Grants of citizenship to nationals of North and South American countries averaged 21,100 annually between 1983 and 1989 before dropping to only 4,900 annually in the 1990s and 10,800 annually from 2000 to 2015.

Figure 3

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

Country of previous nationalityNumberShare of total
South Africa4,7884%
United States2,9082%

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The demographic profile of naturalising citizens leans toward the young and female, as shown in Figure 4. In 2015, 51% of adults receiving citizenship were female. Including children, the distribution was 44% adult women, 42% adult men, and 14% children.

Figure 4

By age group, adults aged 25-44 comprised the majority of naturalising citizens (65% of the total). Only 14% were 45 and older; 14% 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 on the part of a foreign national to apply to become British. Therefore, one might expect that naturalisation is more likely when there are few legal barriers, when naturalisation brings greater benefits, and when naturalising does not mean giving up much of value, such as a previous citizenship. Strands of research have investigated each of these aspects of the determinants of naturalisation rates.

First, naturalisation rates are indeed 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. However, although it 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; British citizenship law now includes many from this list (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 2015, 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 42% of all refusals in 2015 (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 (532 people), as shown in Table 2. The most common reason for refusal was the failure to meet the ‘good character’ requirement. Refusals due to delays in replying to enquiries from UKVI risen in recent years – from 423 in 2013 (6%) to 1,251 in 2015 (12%).

Table 2 – Reasons for refusal, naturalisation applications, 2015

Reasons for refusal2013Share2014Share2015Share
Not of good character229534%109519%452142%
Residence 226433%122421%282627%
Delay in replying to enquiries from UKVI4236%123422%125112%
Parent not a British citizen5538%5109%7497%
Insufficient Knowledge of English and KOL621%4899%5325%
Incomplete applications68710%72813%2542%
Oath not taken in time00%60%140%
Total refusals6,820570910,642

On the other hand, British citizenship law does not have many jus sanguinis characteristics, making it relatively easy for children born in the UK to non-British parents to be registered for British citizenship. 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 naturalisation rates for Zimbabwean migrants to the UK.)

Research on the individual determinants of naturalisation – the ways in which the costs and benefits to individuals determine their likelihood of naturalising – has been conducted mainly in North America and not in the UK (Bloemraad 2006). A recent European study of naturalisation identifies nine factors associated with higher naturalisation rates. At the individual level, naturalisation is more likely for migrants who speak the destination country’s language, who have a parent born in the destination country and who reside longer within it. In addition, people who came from a poor or unstable country or from a former colony of the destination country are more likely to naturalize. Among the second generation (children of migrants), naturalisation seems to be less common among Muslims than among others. In the destination country, the study finds higher naturalisation rates where citizenship law is relatively permissive and where net migration rates are low (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 national 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 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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