Bloomberg: Chancellor of the Exchequer Alistair Darling will announce measures in his budget to make utilities cut bills for Britain’s poorest consumers and give companies tax incentives to buy less polluting cars, a person with knowledge of the plans said. The energy proposals would force companies such as Centrica Plc’s British Gas unit and Electricite de France SA to slash extra costs imposed on households who use prepayment meters. The chancellor will also unveil plans to allow companies …