Allied is one of those films that defies logic. It has all the ingredients needed to make a potential classic, as it has Robert Zemeckis (Back To The Future) on directing duties, Steven Knight (Locke) on the script and Brad Pitt (Fight Club) and Marion Cotillard (Macbeth) in starring roles. So how they managed to create a load of over-stylised nonsense is mindbogglingly frustrating, but the usually reliable director has pulled it off. The story kicks off with an introduction to Pitt’s character – a Canadian spy working for the British army – as he is air dropped into the…