Firms employing fewer than 250 people account for a fifth of Britain's carbon emissions, according to the Government, but a survey by the Carbon Trust found that nearly 70 per cent of small and medium-sized companies have done something about reducing their emissions. If you work for such a company, why not suggest taking some simple steps to cut its energy use such as lowering the temperature of the heating, switch off non-essential equipment overnight or replace your light bulbs with compact fluorescent ones.