UK law is extremely complex because they had to take into account so many possibilities..and at the moment..I can’t remember for sure.
That may be the one where you had to register before the 18th birthday.
Some citizenships you got automatically and others you had to register.
I am thinking illegitimate born of British citizen on UK soil was a register one but not for sure.
Something just came to me...didn’t Obama say that he had to register for his citizenship before his 18th birthday and he did not?
This might fit into the born in Kenya deal with no marriage
If he had been born of a valid marriage in the US would he have had to register or would he have gotten it automatically. I can’t remember. I think automatically.
The question would be if the mother had the kid in Kenya and no marriage then no way he was American NBC.
If the kid was born in HI a bastard - was he NBC? She was also too young I think to confer NBC to the baby.