There is a nominal risk of you getting charged £1000 if you do not return the BRP within 5 days of the naturalisation ceremony. However, we have not heard of anybody actually getting fined that amount.
teddybear79 wrote: ↑Thu Jul 15, 2021 11:37 pm
your brp card is no longer valid , you cannot return on this brp card
That is true. But in this case, the BRP serves the purpose of allowing the OP to board a flight back to the UK. While the BRP (or more accurately the underlying ILR) is invalidated by the naturalisation ceremony, the airline will allow the OP to board the flight.
Once the OP is at the UK border (at the sea/airport), the Immigration Officer will be able to verify that they are a British citizen and will let them through.
To the OP: be aware that there may be significant delays at the British airport after arrival while the Immigration Officers check your immigration status, if you are not carrying a British passport.
I am not a lawyer or immigration advisor. My statements/comments do not constitute legal advice. E&OE. Please do not PM me for advice.