First UK passport application - keeping the other passport?

Hi all,
I'm applying for my first UK passport and after reading through the government website this caught my eye:

You have a certificate of naturalisation or registration
You’ll need both:

• your naturalisation or registration certificate
• the passport you used to come into the UK or the foreign passport you’re included on

The second one is interesting in two ways.
1. Does this mean, if I entered the UK for the first time using my EEA national ID card that I can send that to them and keep my EEA passport?
2. Does this mean, if the passport that I had at the time when I entered the UK for the first time is now expired and got renewed (corner is cut) that I could send that passport instead of the current one?

If all fails, is there a way to apply but either keep or get back my current foreign passport ASAP?

Reason for the questions is, I'm okay to accept that there's no fast track application to receive a first UK adult passport, but it would be great if I could apply and still have my current EEA passport handy for travelling while the UK passport application is slowly being processed. Cheers.

Just submit your current passport, that was fine in my case. Your one with the corner cut is "cancelled" and doesn't need to be sent. Processing times are much faster than the AN application, it could be as little as two weeks.