Thanks for your prompt reply.
From your answer, am I safe to assume that I can use their Nigerian birth certificate to apply for their British passports say online while I am here in the uk? What other requirements would I need?
Are there any additional forms I need to fill in. If so, could you direct me to the right forms or websites please.
Also, will I need to verify my paternity before I can apply for their passports?
In completing the passport application forms, I will need a referee, can I use a sworn affidavits/oats in court for this process or I will have to use a professional person that can verify that he/she has seen them and can attest that they are mine.
Finally, what's are the cost for the forms needed.
Thanking you in anticipation.