EU Car Makers Manipulating Fuel Efficiency Figures

pev writes with a report in The Guardian that "European car manufacturers are rigging fuel efficiency tests by stripping down car interiors, over inflating tyres, taping over panel gaps and generally cheating. This overestimates the figures by 25% to 50%. One would have thought that a simple clause stating that cars have to be tested in the conditions that they are sold in would have been obvious?"