Metro: Hard-up drivers of the most polluting cars must be helped to meet a planned tax increase, a report by MPs has said. They could be hardest hit of the 9million motorists who will end up paying more vehicle excise duty, the Commons environmental audit committee warned. But the tax changes had been poorly communicated which ‘breeds suspicion, increasing the perception of them as revenue-raising measures with no environmental purpose’, the MPs said. Up to 1.1million owners …