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Guide reference: Domestic Records Information 49
Last updated: 9 March 2010

1. Why use this guide?

Use this guide if you are looking for records of how, when or if a person obtained British citizenship or the lesser status of denizen.

You will find information on the different types of naturalisation or denization documents at The National Archives, how to search for these records and some background information on the subject.

You may wish to start your research by consulting our brief guide on Naturalised Britons.

For information on how to obtain a copy of a certificate of British citizenship between 1 January 1949 and 30 September 1986 or a naturalisation issued between 1 January 1981 and 1 January 1986, please read Certificates of British citizenship instead.

2. Essential information

2.1 Some definitions

The following definitions refer to the meaning of these key terms as used in this guide.

Aliens - people from foreign countries outside of the British Empire

Denization - legal process granting limited naturalisation to aliens

Dominions - semi-autonomous countries in the British Empire, including Canada, Australia, New Zealand and South Africa

Naturalisation - legal process granting aliens full citizens' rights

2.2 The evolution of naturalisation, denization and citizenship

The various British nationality acts and British nationality and status of aliens acts since 1708 indicate the requirements necessary for individuals wishing to become British subjects. View copies of the Public parliamentary acts online.

The majority settling in the United Kingdom before 1844 did not go through the legal formalities of applying for naturalisation or denization.

Before 1844 naturalisation was granted by a private act of parliament. Until 1844, the procedure for naturalisation was expensive and only a few could afford it. Those naturalised by an act of parliament received the rights of a natural-born British subjects.

After 1844, naturalisation was extended to the Secretary of State for the Home Office. From 1844 the majority of naturalisation records fall in the department code HO.

Denization on the other hand, required a payment for letters patent to become an English subject, protected by the Crown and English law. Those granted denization were still subject to alien rates of tax, unable to vote, hold civil or military office or inherit land.

The British Nationality Act 1948 created the new status of citizen of the United Kingdom and the colonies. Under this act, people from former colonies and self-governing countries of the Commonwealth could register as UK citizens.

3. Naturalisation certificates (1844-1986)

Records of naturalisation certificates are scattered across several record series and are accessed in a variety of different ways, depending on when they date from and the circumstances in which the certificates were issued. The main series, where the majority of certificates are filed, is HO 334. When searching for a certificate you will need to know which of the following three types of people the certificate was issued to: 

3.1 Foreign nationals applying for citizenship having moved to the UK (1844-1986)

  • 1844-1873 - naturalisations were recorded, or 'enrolled', on documents known as close rolls during this period. The close rolls are in series C 54, a printed index to which is available only at The National Archives building in Kew, series C 275. To use the index and view the rolls themselves you will need to visit us. The index, found in the Map and Large Document Room, is arranged by years so you will need at least a rough idea of when the naturalisation took place (look at the case papers in HO 1 first if you don't know the year of naturalisation - see section 4). On consultation of the appropriate section of the index you may find a name entry for the person who was naturalised, along with a number that will form the key part of your C 54 reference. For more advice speak to staff on site
  • 1870-1912 - search by name in record series HO 334 on Ancestry.co.uk and download (£There may be a charge for accessing this information. Searching indexes may be free.) naturalisation certificates and declarations of British nationality for these years
  • 1913-May 1969 - search by name in record series HO 334 using the advanced search in our catalogue; these certificates summarise information contained in the case papers (see section 4). Read Appendix 1 for more details about certificates' prefixes issued during this period
  • June 1969-1980 - search by name in record series HO 409 using the advanced search in our catalogue for index entries to the naturalisations (the Home Office did not keep a set of duplicate certificates issued in the UK for foreign nationals during these years so the index is the only source of detail)
  • 1981-1986 - apply for duplicate certificates through our Certificates of British citizenship page
  • 1 October 1986 onwards - contact UK Visas and Immigration

3.2 Foreign nationals applying for citizenship from overseas (1915-1982)

In most cases these were for foreign nationals who were resident in British dominions (before 1948) or British colonies who wished to become naturalised Britons.

3.3 Residents of British colonies, former British colonies and Commonwealth countries registering citizenship status (1949 onwards)

Up until 1949 citizens of any colony in the British Empire were automatically considered British subjects.

From 1949, under the terms of the British Nationality Act 1948, people in British colonies and self-governing countries of the Commonwealth could register their British citizenship to remain British citizens - whether or not they actually moved to the UK. This was not the same as naturalisation, which applied only to foreign nationals.

From 1981 the distinction between foreign nationals and people from the Commonwealth and former colonies ceased to exist - they were all obliged to apply for naturalisation to become British citizens. With this change, so the distinction between naturalization and applying for British citizenship also ceases to exist and the terms become interchangeable.

4. Naturalisation case papers (1844-1996)

4.1 What are they?

Case papers comprise of standard forms individuals filled out as part of the process of applying for naturalisation. Case papers rarely survive if naturalisation was applied for but not granted. Case papers provide more detailed information on the applicant than the naturalisation certificate.

They may contain the following information:

  • nationality
  • profession
  • family details
  • birth date
  • birth place
  • address of the applicant
  • character reference(s)
  • police report (after c1878)

4.2 How to find a case paper

Home Office background naturalisation papers to applications are in:

Some of these papers can be searched by name using Discovery, our catalogue, to locate a full document reference (HO 45/4885 as an example). For guidance on how to do this, read Naturalised Britons.

Not all documents in HO 405 are open to view. If the document is closed, you can submit a Freedom of Information request.

Of all the aliens' files created for those entering Britain between 1934 and 1948 in HO 405, only about 40% survive and those that do survive are those where the individual went on to be naturalised as a British citizen.

5. Naturalisation by private Acts of Parliament (c.1700-1947)

The original private Acts of Parliament are kept at the Parliamentary Archives from 1497.

Parliament Rolls in C 65 contain an incomplete set of private acts. Naturalisation by the taking of the oaths of allegiance and supremacy in court can be found in KB 24 and E 169/86. The information from these rolls has been published by the Huguenot Society (volumes XXVII and XXV).

5.1 Published private Acts of Parliament up to 1900

Indexes to naturalisation have been published by the Huguenot Society and copies of these are available at The National Archives, among the HO series lists.

5.2 Indexes to Private Acts of Parliament (1900-1947)

Consult the Index to Local and Personal Acts (HMSO, 1949).

5.3 Foreign Protestants living in America (1740-1772)

Between 1740 and 1772, foreign Protestants living in America could become naturalised British citizens after seven years' residence.

Every year lists of those naturalised in series CO 5 had to be sent to the commissioners for trade and plantations in London, where they were copied into entry books (in CO 324/5). Over 7,000 foreign Protestants took advantage of this. Look in MS Giuseppi in the Huguenot Society volume XXIV for a list of the names.

6. Denization records (pre-1509-1873)

Letters patent of denizations are enrolled in the patent rolls in C 66, with supplementary patent rolls in C 67.

Denizations before 1509 can be traced through the indexes to the Calendar of Patent Rolls. Look under words such as 'denizations' or 'indigenae' in the indexes to early volumes.

For the period 1509 to 1800, indexes to denizations have been published by the Huguenot Society. A copy of these, together with a typescript index to denizations between 1801 and 1873, is available among the HO series lists in the reading rooms at The National Archives.

The references found in the indexes to denizations refer to original documents in HO 1 and HO 44, C 97 and HO 4 consist of original letters patent of denizations which were left unclaimed by the patentees. There is a name index to C 97 for the period 1751 to 1793, but not for HO 4 which covers the period 1804 to 1843.

The Westminster denization roll is held at Westminster Abbey Muniments and Library.

7. Appendix 1: prefix to naturalisation or British nationality certificate numbers

Naturalisation Act, 1870
A Certificate (ordinary) to a person with five years residence in the United Kingdom during the eight years immediately preceding application for Naturalisation
AA Certificate to person with five years service under the Crown during the eight years immediately preceding application for Naturalisation
AAA Certificate to person in the Diplomatic or Consular Service with five years service under the Crown during the eight years immediately preceding application for Naturalisation
B Certificate to person who has already been granted a Certificate of Naturalisation under the Act of 1844
C Certificate to a person of Doubtful Nationality with five years residence in the United Kingdom, or five years service under the Crown, during the eight years immediately preceding application for re-admission
D Certificate of re-admission of person to British Nationality with five years residence in the United Kingdom, or five years service under the Crown, during the last eight years immediately preceding application for re-admission
E Declaration made by a person, a subject of a foreign state subsequently naturalised as a British subject, renouncing British nationality
F Declaration by a person, an alien by origin but born within HM dominions, renouncing British nationality
G Declaration by a person, born out of HM dominions of a father being a British subject, renouncing British nationality
H Declaration by a natural-born British subject, renouncing subsequent Naturalisation in a foreign state
British Nationality and Status of Aliens Act, 1914
A and AZ Certificate (ordinary) granted under Section 2 of the Act, where the names of children are not included
B and BZ Similar to Certificate A, but including the names of children
C and CZ Certificate granted under sub-section (2) of Section 5 of the Act to a minor
D Special certificate granted under Section 4 of the Act to a person with respect to whose nationality a doubt exists, where the names of children are not included
DZ Certificate of Naturalisation granted to a woman who was at birth a British subject and is married to a subject of a state of war with His Majesty
E Similar to Certificate D, but including the names of children
EZ Similar to Certificate DZ, but including the names of children
F Certificate granted under Section 6 of the Act to a person naturalised before the passing of the Act, where the names of children are not included
FZ Certificate of Naturalisation granted to a French national where the names of children are not included
G Similar to Certificate F, but including the names of children
GZ Similar to Certificate FZ, but including the names of children
M Special Certificate granted under Section 4 of the Act to a person with respect to whose nationality a doubt exists
O Certificate granted under Section 8 of the Act by the Government of a British Possessions overseas
British Nationality Act, 1948
BNA Application made by a subject of a foreign state resident in the UK
M s7 & 18 1948 Act: application for registration of a minor child
O Application made by a subject of a foreign state resident overseas
R1 s6(1) 1948 Act: application made by an adult British subject or citizen of the Republic of Ireland, or any of the Channel Islands, Isle of Man, a colony, a protectorate or a protected state to which s8(1) of the Act applied, or a UK Trust Territory, or on the grounds of Crown Service under HM Government in the UK
R2 s6 (2) 1948 Act: application made by a woman who has been married to a citizen of the UK and colonies
R3 s6 (2) 1948 Act: application made by a woman who has been married to a citizen of the UK and colonies
R4 s12 (6) 1948 Act: application made by a person who but for his citizenship or potential citizenship of one of the countries mentioned in s1 (3) of the Act would have become a citizen of the UK and colonies under s12 (4) of the Act
R5 s16 1948 Act: application to resume British nationality by a person who has ceased to be a British subject on the loss of British nationality by his father or mother in accordance with s12 (1) of the 1914 Act
R6 s19 1948 Act: declaration of renunciation of citizenship made by a citizen of the UK and colonies who is also a citizen of one of the countries mentioned in s13 of the Act or of the Republic of Ireland or a national of a foreign country

8. Further reading

Some or all of the publications below may be available to buy from The National Archives' bookshop. Alternatively, search The National Archives' library catalogue to see what is available to consult at our site in Kew.

Roger Kershaw, Migration Records for Family Historians (The National Archives, 2009)

Roger Kershaw and Mark Pearsall, Immigrants and Aliens: A Guide to Sources on UK Immigration and Citizenship (The National Archives, 2004)

Guide reference: Domestic Records Information 49

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