Take a taxi from the headquarters of British Sky Broadcasting in Isleworth, west London, and chances are you will be driven away in an electric hybrid car. Your greenhouse gas emissions will be lower than in a standard cab and, although you should not feel quite as virtuous as if you had taken a train or a bus, your impact on global warming will be comfortingly small.

BSkyB recently became one of the world’s biggest companies to turn “carbon-neutral”, and transferring its taxi account to Green Tomato, a “green” cab company, was just one of a raft of measures designed to cut the broadcaster’s greenhouse gas output. It joins the bank HSBC, the recent World Cup in Germany, the hedge fund Man Group and the advertising agency Euro RSCG in a select group of organisations and events that have pledged to cut their impact on the climate to zero.