Oliver Krischer, the party’s deputy leader, told Germany’s N24 television channel: ‘The government told us in July that it knew about this software, which has been used in the USA, and it’s clear they knew the software was widely in use.’

He added: ‘The government worked with the auto industry not to see that emissions levels were reduced, but so that the measuring system was set up to allow the cars to meet the necessary standards on paper.’

Mr Krischer’s claim centres on a written answer given by the German transport ministry on July 28 to a question from the Greens about so-called ‘defeat devices’. This is the industry name for the software that allowed Volkswagen to cheat emissions tests in the US. The ministry wrote that it shared the view of the European Commission ‘that there is no extensively proven means of preventing defeat devices’.