A Porsche Cayenne on the road in Berlin. Transport minister Alexander Dobrindt says it has been established the 3-litre model contains illegal software that only activates its emissions control system in lab tests © Getty

Germany’s diesel cheating scandal widened on Thursday as the country’s transport minister ordered a recall of Porsche’s three-litre Cayenne model, saying it contained illegal software to get round emissions tests.

Alexander Dobrindt said the government would also ban the registration of any Cayennes still being sold until updated software was available.

His intervention, which will affect 22,000 cars across Europe, came as Germany’s environment minister, blamed the woes of the car industry on its excessively close relationship with the German government.

Barbara Hendricks said there had too often been “a lack of distance” between the government and carmakers and the close relationship “may have lulled the auto industry into a false sense of security”. As a result it had not invested enough in new technology such as electric vehicles.

This now had to change, she said, “since the previous policy had been interpreted by management . . . as carte blanche for manipulation and abuse”.

Ms Hendricks’ comments were the first reaction by a member of Angela Merkel’s cabinet to news that European regulators were investigating allegations that Germany’s largest carmakers had for decades colluded over technology.

With weeks to go before September’s Bundestag elections, public concern about the scandals plaguing the sector — as well as worries over the future of diesel technology — could feature heavily in the campaign.

Next week government ministers, carmakers and regional officials will hold a “diesel summit” designed to address the growing problem of pollution from the fuel in German cities. Some towns are already discussing bans on diesel vehicles to cut harmful emissions.

Ms Hendricks said the government should try to restore trust in the sector by moving certain regulatory functions — such as type approval for new cars — from the transport to the environment ministry.

Her statement, delivered at the headquarters of Volkswagen in Wolfsburg, was an extraordinary broadside against an industry that employs 800,000 people in Germany and accounts for a fifth of the country’s industrial revenue.

But it reflects growing frustration in Berlin over a string of scandals that have tarnished Germany’s reputation for engineering excellence and thrown one of the most important sectors of the economy into disrepute.

The claims came as VW continues to suffer the after-effects of the diesel scandal, which first erupted in 2015 when US regulators revealed the company had installed cheating software in millions of vehicles to get round emissions restrictions.

The latest blow came with a report in Spiegel last weekend alleging carmakers VW, Daimler, BMW, Audi and Porsche had colluded for decades on prices, technologies and the choice of suppliers.

Mr Dobrindt said it had been established that the Porsche Cayenne sport utility vehicle also contained illegal software which only activated the car’s emissions control system in official lab tests and switched it off when it was on the road. Porsche, a VW subsidiary, uses engines made by Audi, another VW subsidiary, for the diesel version of the Cayenne.

Some of the companies have defended themselves against the claim of collusion. VW, without addressing the allegations directly, said co-operation among carmakers on technical issues was a common industry practice that helped to foster innovation.

“This brings benefits in many respects, not least for customers, because innovative solutions become available more quickly and at a lower price than costlier individual solutions,” the company said on Wednesday after an extraordinary meeting of its supervisory board.

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