Passport application booklet, page 14, Table A:
Apply for a passport, page 14 wrote:Applicants born or adopted in the UK – parents’ or adoptive parents’ details.
To support your claim to British nationality, please provide evidence under either 1 or 2. We need to see:
- Evidence of one of your parents’ claim to British nationality at the time of your birth
- their British passport number (provided in Section 4 of the application form) or
- full birth certificate, or
- certificate of registration or naturalisation, and
- if this is your father, also provide his marriage certificate to your mother. (This does not apply for those born or adopted on or after 1 July 2006 or same-sex adoptions.)
- Evidence of one of your parents’ immigration status in the UK at the time of your birth
- their passport at the time of your birth, and
- if this is your father, also provide his marriage certificate to your mother. (This does not apply for those born or adopted on or after 1 July 2006 or same-sex adoptions.)
So based on that, I would say that you should send your expired passport (and BRP showing your ILR status, even though they don't specify it). Given that your naturalisation application will probably be decided in the next month or two, you should apply for your daughter's passport as soon as possible, while you still have the original BRP showing your immigration status at the time of her birth.
As I'm sure you know, you have to send your BRP card back within 5 days of attending your citizenship ceremony. You should get a certified copy of it made (the Post Office have a
document certification service) before you send it back, in case you ever need to provide proof of your immigration status at the time of your daughter's birth again. It might be years before you need it, (or you may never need it at all), but better safe than sorry. There are a number of people who have written on this forum about being unable to prove they're UK citizens at birth because the documentation of their parents' status has been lost.
