Now is the moment for layering up to keep the cold at bay and to stay cosy in style. The good news sartorially speaking is that cardigans aren't just layers; they're a vibe. From effortlessly chic to casually cool, these are the knitted pieces that are set to be our constant companions through the winter – and, in all likelihood, through spring too – adding warmth, dash and a shot of colour to our AW wardrobe.