I need to know, for a story, what a man would exclaim upon suddenly finding out that a friend of his is homosexual. [and by suddenly, I mean he sees a photo of the friend naked in bed embracing another man.] If the character were American I would know how to choose whether, for instance, "holy shit, you're gay??" or "holy shit, you're a fag??" was more appropriate for the character. But I don't know enough to make that kind of judgment for British terms and colloquialisms, both in terms of referring to homosexuals [queer vs. poof vs. _____??? i have no idea] and in terms of expletives/exclamations of surprise.
So, I turn to you guys for help. The character is from the London area, male, in his mid-20s, lower-class, a petty criminal, not significantly more homophobic than the average (and not significantly less, either). What might he exclaim upon suddenly learning that a friend of his was gay? (The friend is older and a bit of a respected mentor, but the character may be too shocked for that to matter much to his initial exclamation.)
Thanks in advance for your help!
[edited to add more details]