The files relate to individual foreign citizens (mostly European) who arrived in the UK between 1934 and 1948 and who applied for naturalisation. All files include application for naturalisation with police reports. Some also include initial application for visa or employment permit, change of name or business name and Second World War internment papers. Files were opened when the individual first applied to enter the UK and continue until naturalisation or death.
Files relating to married couples are listed under the name of the husband and the wife's file is attached to the husband's. Spelling of names sometimes varies throughout the files. The name listed is that used on the naturalisation certificate (where issued) or applied for but they are listed only by surname and initial letters with alternative names being noted as 'aka' (also known as) or 'formerly'. All possible variants of a name should be used when a search is being conducted.