Transport minister Alexander Dobrindt said that vehicles in Europe with 1.6 and 2.0-litre diesel engines were also affected by the manipulations in the US.

Mr Dobrindt also said spot tests would be carried out on other carmakers: "It is clear that the Federal Office for Motor Traffic will not exclusively concentrate on the VW models in question but that it will also carry out random tests on vehicles made by other carmakers."

Already shares at BMW have fallen after a report claimed that the X3 xDrive 20d sport utility vehicle exceeds European emissions limits in testing.

According to reports, Audi research chief Ulrich Hackenberg, Porsche research chief Wolfgang Hatz, and VW US chief executive Michael Horn are to be dismissed by the VW board tomorrow.

Meanwhile prosecutors in Lower Saxony in Germany are said to be considering launching a preliminary investigation into Volkswagen employees.

Calls for a new testing regime continue to be made in the UK and Europe. Louise Ellman MP, chair of the Transport Committee in the UK, said: “There are questions over whether the testing authorities commissioned by motor manufacturers are truly independent. Do the results found in test conditions truly reflect real life situations on the road?

“It is vital that the UK Government, the authorities in Germany and in the European Commission take action to clarify the extent to which vehicles on UK and European roads are affected by the issues that have ben identified in the United States. They must take steps to restore public confidence.”