It has been nearly a week since the Environmental Protection Agency accused Volkswagen of using a “defeat device” to cheat on emissions tests.

A team of ICCT technicians in California discovered the software after trying to understand an unique set of results found by European emissions tests on Volkswagen cars. The European Union presently allows manufacturers to optimize results with tactics such as stripping the auto of excess weight or removing the air conditioner, a German company that performs tests for carmakers.

BMW officials said they “were willing to discuss our testing procedures with the relevant authorities and to make our vehicles available for testing at any time”.

The BMW Group does not manipulate or rig any emissions tests. “We observe the legal requirements in each country and adhere to all local testing requirements”, BMW said. BMW said that there’s no system in its cars that responds to tests differently than it would operate on the road.

ICCT research has previously suggested that excessive nitrogen oxide emissions – which can exacerbate respiratory conditions such as asthma – may not be exclusive to Volkswagen.

Indeed, experts said it could very well be that the high levels of real-world emissions reflected in the ICCT report show not that firms are cheating, but only that it’s all too easy to design a vehicle that passes governmental lab tests for emissions. Its shares have been slammed, CEO Martin Winterkorn has resigned, and prosecutors in the US and Germany are considering legal action.

Germany’s motor vehicle administration “will concentrate its investigations not only on the Volkswagen models in question but will also do spot checks of other vehicle manufacturers”, Transport Minister Alexander Dobrindt told reporters in Berlin.

The consumer watchdog is investigating whether Australian drivers have been misled by Volkswagen.

The 2015 BMW X3 was a Euro spec vehicle that came out at 11.88 time more than the Euro 6 limit for emissions.

VW said on Tuesday about 11 million of its cars worldwide were fitted with the software that was found to be cheating emissions in the United States.

Months ago, BMW might have been given the benefit of the doubt, today, the poor emissions performance breeds suspicion. “At the BMW group, there are no specific activities or technical provisions which influence the emissions recorded during the test mode”, said a spokesman. “Adding a proxy of suppliers to the equation, it accounts for roughly 1.5pc of German employment and even more when it comes to the growth impact”, Mr Brzeski said.