Comedy about the police is nothing new. Nor is drama. Put them together and you might have something innovative; but the result would need to be better focused than Babylon (9 February).This 90-minute pilot episode for a forthcoming series, written by Peep Show writers Sam Bain and Jesse Armstrong, and directed by Danny Boyle, was about as trendy as you could get.It showed the Metropolitan Police force caught in the maelstrom of modern communications. Everything that happened in the real world was “live-tweeted”, and the 24-hour news stations knew more about what was happening on the streets than the ­commissioner and his vast press office. It was chaos.Into this mess dropped a smooth-talking American PR woman, Liz Garvey (Brit Marling) hired from Instagram at vast expense