To get a UK citizenship and passport for a descendant, you must first be a UK citizen by birth or be a naturalized British citizen. If you have a British mother and were born between 1961 and 1983, you may be eligible for British citizenship. According to the British Embassy, children born after December 31, 1982 in the United States (whose fathers are British citizens) may also be British citizens by descent.
Getting a UK Citizenship for a Descendant
Complete form MN1, available at the UK Border Agency website (see Resources) if your child is under 18. You will need to apply for citizenship through entitlement or naturalization if your child is over 17.
Follow the MN1 instructions by completing the form legibly (in capital letters) in black or blue ink. Include the child's name, birth date and place/country of birth. Your child must satisfy the citizenship criteria under British nationality laws and be of good character if he is over 9 years old.
Submit the application fee and include required documents, such as copies of birth certificate, child's passport, parents' marriage certificate or civil partnership certificate, court order/deed (if citizenship is being submitted by a guardian). Be sure to sign and date the form.
If you live in the UK, mail the completed application to:
UK Border Agency (Department 1) PO Box 306 LIVERPOOL L2 0QN
If you live in the Channel Islands or the Isle of Man, send the form to the Lieutenant-Governor. Or, if you live elsewhere, send the form to the nearest British Consulate, Embassy or High Commission (see Resources).
Wait for approval and follow any instructions for your descendant's citizenship, including affirming the oath of allegiance to Her Majesty the Queen to finalize the citizenship.
Getting a UK Passport for a Descendant Born in the USA
Upon receiving citizenship for your descendant born in the USA, contact the British Embassy in Washington or visit www.ukinusa.fco.gov.uk to apply for a passport.
Fill out all required documents and complete the requisite forms. Forms should be printed out in black and white. Initial each page on the form box that says, "Please initial here." A thumbprint may be used if an applicant cannot initial her name, along with a letter of explanation from her doctor or relative.
Get passport photographs taken. Ensure that the photographs meet passport standards set by the International Civil Aviation Organization and are set against a white background.
Submit two recent and identical photographs along with supporting documents and fees. This may include the child and mother's UK birth certificates (for children born on or after July 1, 2006 in the UK); father's UK birth certificate/naturalization and marriage certificate or mother's declaration; child's birth certificate or naturalization document (for children born on or after July 1, 2006 outside the UK); or the father's UK or British Overseas Territories birth certificate/naturalization and marriage certificate or mother's declaration.
Attend any interviews with the Identity and Passport Service to confirm your child's identity if he is 16 or older.