Parents have ILR, but sone doesnt - can he travel?

[MarkAlan]

Myself and wife obtained ILR last year, but we didnt apply for our 3 yr old son (born here and live whole life here) as were aware he could register for British citizenship once one of us got ILR.
At birth he was added to my wife's visa. Which obviously is no longer in existence now she has ILR.

We relaised we havent registered him yet.
We are travelling abroad in 10 days. He will be travelling on his US passport.
Do we need to get a visa or citizenship for him so he can be let back in the country when we return?
Or will he be OK?

Urgent advice needed.

Many thanks

[MarkAlan]

Further to this, is this an option
1. Apply for his BC now using MN1 and NCS today
2. Travel as required on US passport
3. Receive (hopefully) confirmation of Citizenship
4. Return to UK once confirmation received *

* My wife returns prior to myself and son so can let us know when the certificate arrives.
She can email scan of the certificate for us to print out to show if needed
(Yes I know we should really have the original with us on arrival but .....)

[vinny]

That should be okay.