I have never met my half brother. He is 10 years older than me and I'm nearly 30, so guessing he's around 40 years old. I do not know his surname.

Oxford where? Oxford, Mississippi maybe?

This is is a global website. Do you have anymore information that could help us?

There are always birth records you could trace at your library or the library where you think your half brother was born, or maybe elder relatives or even websites that can trace your ancestry may yield you more information to help your search.

I would be careful about putting too much personal information on unsecured public websites though.

Oxford in the UK.
I don't have anymore information and my father doesn't know anything as he was 17 at the time and the mother left with her son, my half brother, shortly after he was born.
I can't search birth certificates as I'm pretty sure his surname is not the sake as my father's.