My eldest son is 19. He was born in France, to an English father and Fench mother, though we are not married, I am officially his father. For the last 2 years he has been sudying at Manchester University, he considers his future to be more in England than France, and as such has shown an interest in obtaing a uk passport. Is he eligible?

An unmarried British father generally cannot automatically pass on citizenship for children born outside UK before July 1, 2006, unless the parents later married (which sounds like not the case here), or the father was domiciled in a country that regarded illegitimate children the same as legitimate children (what was your domicile?).

The child could also have been registered as British before age 18 but that is too late now.