Paul Watters, head of roads policy at the AA, said: “We do know that most accidents happen in the dark, its also comforting for people, especially if they arrive back from somewhere in the night, when they have got a late train. There are also suggestions that it increases crime. So it may save money in terms of energy but then you have to look at the cost in terms of security, safety and accidents, it may actually be more. We have even heard that some milkmen are having more trips and falls, so it has had some implications you might not think about.