....... Oh so you are saying every illegitimate kid of a British father can’t claim British citizenship? Riiiight.
You better read the law. Start with my profile. The marriage was Void Abinitio. Read up about VOID marriages and ILLEGITIMATE CHILDREN.
Also, Obama would not have been a Kenyan citizen either. The only way he can get Kenyan citizenship is to go over there and live and some other various requirements BECAUSE he was not a British citizen.