Other carmakers and EU in the hot seat on VW scandal

The plan concerns 5 million Vokswagens, 2.1 million Audis, 1.2 million Skodas, and 1.8 million vans in addition to the 700,000 Seats.

The engines of the vehicles were fitted with software that detected controls for nitrogen oxide (NOx) and modified the engine's performance and emissions.

The people who installed the systems "acted criminally - they must take personal responsibility”, said Olaf Liess, the social-democrat economy minister of Lower-Saxony, the German region where VW is based.

Liess is also a member of the carmaker's board.

"Huge damage has been done because millions of people have lost their faith in VW”, he added, speaking to the BBC.

The scale of the scandal is now putting other carmakers under scrutiny.

A study by the environmental NGO Transport & Environment (T&E) has showed that some diesel cars use up to 50 percent more fuel on the road that in laboratory tests.

Models include the BMW 5 series, the Peugeot 308, and the Mercedes A, C, and E class cars, which "have the biggest average gap between test and real-world performance”, T&E said.

"The system of testing cars to measure fuel economy and CO2 emissions is utterly discredited”, it added.

"The gap between test results and real-world performance has become a chasm, increasing from 8 percent in 2001 to 31 percent in 2012 and 40 percent in 2014. Without action this gap will grow to nearly 50 percent by 2020”.

"Carmakers, not drivers, are the cause of the problem”.

Meanwhile, questions are also arising over the European Commission's knowledge of the flawed emissions tests.

In 2011, the Commission's Joint Research Center published a study showing that road tests revealed NOx levels 14 times above EU limits.

In 2014, a Commission expert also warned about "the possibility for 'cycle beating’,” referring to cheats in approval tests, the Wall Street Journal says.

EU authorities did not take action, however.

On Tuesday, industry commissioner Elzbieta Bienkowska met with Herbert Diess, the head of Volkswagen’s passenger brand.

The Commission was not available to comment on the meeting Wednesday morning. But spokesman Ricardo Cardoso said before the talks that the Commission "expects VW to explain the situation".

"The Commission wants facts and it expects VW will collaborate fully with national authorities and expects compliance with EU rules”.