There is a storm coming. I can feel it as I stand on a street corner in south London, thinking about my daughters. Lily and Rose are both 11 years old. One is crazy about dogs, the other loves owls. They are at that tender age when the hormones have begun to stir, and they could be stomping around the room like furious teenagers one minute but snuggling up for a cuddle the next. The girls are fast approaching 13, the age that Chevonea Kendall-Bryan was when she leaned out of one of the windows on the fourth floor of a block of flats on this street. A boy she knew was down here on the ground, but this was not Romeo and Juliet. Far from it. A report for The Sunday Telegraph