Huge owl

Hey, was walking at dusk this evening and heard something hissing at me from a tree, looked over and there was a giant owl looking at me, far too big to be a barn or a tawny, a car also came past and it didn't do anything but hiss, too clear things up, the owls head is at the branch he is perching on, and the tail is the thing sticking up (I thought it were ears at first!) any idea what this is? It must have been at least 1 and a half feet tall. (picture below)