When were you born please?
Was your father born in the UK before 1983?
Thanks. Drafting your answer now.
Sorry, please also state when you were born?
Thank you for your question and patience, I’m Tom and I’ll try to help you.
If you were born outside the UK before 1983 to a British father who was born in the UK and you mother and father were married at the time of your birth then you are automatically a UK citizen by descent.This means that provided you can prove the above facts of your birth then you can apply for a UK passport without having to register as a UK citizen first.
However, you should check that Belguum allows dual citizenship (I think it does), provided it does then you can apply for a UK passport.
My goal is to provide you with a good service. If you feel you have received anything less, please reply back as I am happy to address follow-up issues specifically relating to your question.