Immigrationboards.com

This may be a well trodden path, and may apply to many, but I haven't been able to find much to clarify the requirement
my wife recently got her British Naturalisation certificate
we are in process of completing her First British Passport application
There is a section that states we should include all her 'in-cancelled passports' with the documentation (as well as a section where we have provided her naturalisation details)
Questions regarding her current, valid passport from her home country, does she have to send this with her Passport application form seems to suggest yes, but anecdotally from friends who have recently applied in the same circumstances, they have they didn't include it with there passport application
So questions
Does she need to include it ?
if so, what does the Passport office do with it, and do they return it ?
we are going to make the application thru the post office checking service, however I would further advice on this, if anyone has any to give
many thanks

She must include it.

HMPO return it.

thanks for your prompt reply
do they just need it for documentation/checking purposes, or do they do anything to/with it,
Is it still valid if she wishes to use it as a travel document, might not be an easy question, and its possible to ask 'why would she', however I would still like to understand her options around this area

also, sorry should have asked this before, her current home passport does NOT include her ILR, that's on an expired one, should she also inclue this passport with her application

They don't "do" anything to it. You are over thinking this.

It is used for identity and name purposes.

ILR is NOT a requirement for a British passport. She is british as she has a naturalisation cert.

She must include all uncancelled passports as the form asks!!

many thanks, much appreciated, I am finding it better to overthink rather than underthink these issues, to be on the safe side

They need the passport because they will only issue a passport if your name matches exactly the name they have. If your other passport has a slightly different name, they will reject your passport application until you get the country to sort out your name.