Short Answer: UK.
Long Answer: Well, "Country of Origin" is a bit of a misnomer. Really, it should be "Countries of Origin". You see, I'm a bit of a mongrel when it comes to cultural backgrounds. So why UK? Well, that's where I was born and brought up; in Newcastle-upon-Tyne in England. Although I'm of mixed blood, I only hold nationality in one country, this being it. There's good reason for that. I could apply for Greek nationality, but then I'd have to do national service, and there's no point really since they're both European Community countries.
At the lowest level, I'm half-English half-Greek. On my mother's side I'm half-English, although her parents hail from the Shetlands and the Orkneys, making me entirely Scottish. (I do have a kilt from in the family, too, before you ask; it was my Great-Uncle Donald's from his time in the army.) The viking blood of those Northern islanders was strongly evident in my grandfather's looks, and it flows in my veins too.
My father is Greek, although he holds triple-nationality: UK from living here enough years, Greek because he is, and Egyptian because he was born in Cairo. A lot of my family lived in Egypt, in Cairo and Alexandria. My grandfather was an accountant and worked for a Dutch textiles mill that had factories around Northern Africa. So for a time my grandparents lived in Lagos and Dakaar amongst other places. I went to these lands as a child, and although there's photgraphs of me standing in the equator in Zaire for example, I'm too young to remember them. I remember the rubber trees, but my clearest memories are of Senegal where we spent a lot of time.
Mostly I look (and act) just like my father, but there are influences from other areas in my background. I have longer legs, thanks to my maternal grandfather, and I have the eyebrows from that side of the fmaily too. My hair is darker than my father's, and has natural red highlights; a trait from my paternal grandmother's roots in Malta.