Volkswagen US CEO Michael Horn tells Congress he knew about emissions in early 2014

Volkswagen has said that 11 million vehicles have been fitted with defeat devices

President and CEO of Volkswagen Group of America Michael Horn attends the 2016 Volkswagon Passat Unveiling at the Duggal Greenhouse on September 21, 2015 (FilmMagic)

The head of Volkswagen in the US will tell the US Congress on Thursday that he knew the company was rigging emissions testing for diesel cars as early as 2014, according to a prepared statement.

In the statement, Michael Horn said that he was told in the spring of 2014 that there were issued with non-compliance on emissions test that could be fixed. He said he was also told that Volkswagen engineers would work with agencies to resolve the issue. By late 2014, there was said to be a plan in place regarding so-called defeat devices, that made vehicles emit higher levels of nitrogen oxides when vehicles were driven in actual road use than during laboratory testing.

“Let me be clear, we at Volkswagen take full responsibility for our actions and we are working with all relevant authorities in a cooperative way,” Mr Horn said.

He added that the company has withdrawn its application for certification of 2016 models and that Volkswagen is “determined to make things right”.

Volkswagen has said that 11 million vehicles have been fitted with defeat devices that pose no threat to vehicle safety, but emit as much as ten times the legal limit of nitrogen oxides, which are toxic to humans.

We at Volkswagen take full responsibility for our actions

&#13; <p>Michael Horn, head of VW US</p>&#13;

Mr Horn said that he has written to affected customers in the US. The company will now implement a recall of vehicles so that emissions software can be updated. Matthias Mueller, Volkswagen CEO, said that this will begin in 2016 and could take the whole year. It also relies on drivers to take the initiative to get their cars updated, to the frustration of environmentalists.