Until now, VW has maintained that the so-called “defeat devices” installed in 11 million cars worldwide could be traced back to the fraudulent intentions of a “small group”.

But the latest revelations show that the years-long cheating of regulators' checks was in fact known to a large proportion of the company's management cadre.

One person familiar with the investigation told Spiegel that the diesel motor at the heart of the scandal, known as model EA 189, had been checked against changing emissions standards in different global markets several times since its introduction in 2008.

“Any motor developer would have been put on guard” by the engine's ability to meet standards without expensive exhaust treatment technologies, another VW manager said.

A Volkswagen EA 189 2.0-litre diesel engine. Photo: DPA

VW's “defeat device” detected when cars were undergoing official emissions testing in the laboratory and switched on a system to clean the exhaust.

But outside the laboratory environment, the system would simply be deactivated by the software, increasing performance – but also the levels of harmful NOx gas emitted in the car's exhaust.

News that the cover-up was wider than previously thought will put extra pressure on Matthias Müller, the new VW CEO who is scheduled to present the investigation's findings to other top managers on Thursday.

He has also promised to come up with a plan to refit the cars which contain the cheating technology and to make savings elsewhere in the company to cover the costs.

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