Before 1844, foreigners wishing to become British subjects (the process known as naturalisation) had to do so by obtaining a private Act of Parliament.
Many thousands of people were naturalised in this way, the most famous being the composer George Frideric Handel in 1727.
Tracing naturalisation records at the Parliamentary Archives
You can search our online catalogue Portcullis for naturalisation acts. Search for your ancestor's surname in the Any Text field, with the year or year range you think it may have happened, in the Date field. If you find anything of interest, make a note of the references and contact us to make an appointment to see it or order copies.
There are printed indexes to naturalisation Acts and other records published by the Huguenot Society. These can be found in large references libraries, at The National Archives, and the volumes covering the period 1603-1800 can be consulted in the Parliamentary Archives searchroom.
A very few people were naturalised by Act of Parliament after 1844.
However in 1844 the Home Office began to grant certificates of naturalisation and these records are in The National Archives: see their Research Guide for naturalisation records for further information. Returns of names of aliens issued certificates of naturalisation can also be found printed among House of Commons Parliamentary Papers between 1867-1962, covering the period 1854-1961.