When lauded Irish writer PP Hartnett told us he doesn’t want to be “the usual safe fag who isn’t going to gamble” in order to get his books on the shelves, we decided we wanted to hear more. Celebrated for his 1996 queer novel, Call Me, he’s since rejected the mainstream to create his own publishing company, collaborated with gay serial killer Dennis Nilsen, and formed a band called Child Rape Photos. As his latest collection of poetry, or what he calls “thought grenades”, is published, he tells Gavin Whelan it’s all in the service of wanting to tell the truth about the ip side