interview by ALEX ISRAEL portrait by ANNABEL MEHRAN All images courtesy of Mark Leckey and Gavin Brown’s Enterprise, New York Mark Leckey, one of the most interesting of the post-Young British Artists, won the 2008 Turner Prize and had a solo exhibition last summer at the Serpentine Gallery. He explores the effect of language in contemporary signifiers: products and brands, entertainment and music, and also contemporary art. Leckey is fascinated by the immaterial properties of physical things, yet rarely makes objects himself, opting to work in film, video, and performance. Leckey was in Los Angeles last fall for a residency at the Hammer Museum. We spoke in a park in Westwood, sitting just yards away from a massive bronze abstract sculpture — not unlike those that populate Leckey’s 2006 video, “The March of the Big White Barbarians.” ALEX ISRAEL — I’ve heard you speak about your upbringing, and how you were,…