How to apply for British citizenship by descent
If you do not have automatic citizenship by descent, and you are eligible to register for it, you can do so by completing an online application form. The form you will need to complete will vary depending on when you were born and the way in which you qualify. You are able to apply by post; however, the processing time for postal applications is significantly longer than applying online.
In addition to completing the application form, you will normally be required to attend an appointment at UK Visa and Citizenship Application Services (UKVCAS) to have your biometric information taken - this is your photograph and fingerprints.
When making an application for British citizenship by descent, you will need to submit a number of supporting documents to prove that you meet all relevant requirements. Supporting documents can be submitted by either uploading copies of the documents via the online service or by having them scanned during your UKVCAS appointment.
Applicants over the age of 18 will also be required to attend a British citizenship ceremony once an application has been completed successfully, there is an additional fee for this.