I scurry up the ladder to tug at his ankles. This time he can't keep his cry to himself. As I dislodge one of his feet from the rung they're desperate to stay on, he lunges upwards to clutch at the gutter. I'm down the ladder in a moment, and in another I've snatched it away. It clatters at full length on the concrete as its owner dangles from the flimsy gutter. "Help," he screams. "Look what he's done. Christ, someone help." He's saying more than...