Guardian: Sniffy neighbours dismissed it as an eyesore, but David and Samantha Cameron believed that a wind turbine on the roof of their west London home would symbolise their commitment to the environment. As Britain freezes this winter, Cameron has been forced to admit that he has abandoned his plan to generate electricity at home after deciding reluctantly that it will never really work. “I haven’t, tragically,” Cameron told the Guardian yesterday when asked whether he had a turbine …