Costing the Earth - Spring Forwards, Fall Backwards

On October 31st we'll all dutifully turn our clocks back by one hour, plunging our evenings into premature darkness. There's mounting evidence that this annual ritual has a real environmental cost. Alice Roberts takes a look at the arguments from the Greenwich Meridian to Cornwall and the Western Isles to find out who could benefit and who might suffer from a change in the way we set our clocks.