How European emission tests can be cheated
A laboratory test carried out for the BBC's Panorama programme shows that Volkswagen diesel cars programmed with a "defeat device" can cheat the official European pollution test, as well as the test in the United States.
The company told the BBC it believes this is the first time the cheating software has been filmed in action.
Volkswagen has admitted it used the device to rig tighter pollution tests in America. But it has been more ambiguous about whether it used the same tactics to actively cheat official European tests.