In the last few days several announcements have demonstrated how the initial exposure of Volkswagen’s cheating US tests is merely the tip of an iceberg of test manipulation. In the US more models, including models from Porsche, have been accused of having illegal levels of diesel NOx emissions. This was followed by VW admitting that it overstated fuel economy and CO2 figures by 10-15% on 800,000 vehicles, including petrol cars. In a further announcement, the environmental group Deutsche Umwelthilfe (Environmental Action Germany, DUH) exposed suspicious test results on an Opel Zafira. General Motors deny any wrongdoing.