Question to the Department for Transport:

To ask the Secretary of State for Transport, what estimate his Department has made of the number of diesel vehicles in the UK that are fitted with illegal defeat devices.

The Driver and Vehicle Standards Agency (DVSA) is investigating a range of Euro 5 and early Euro 6 diesel vehicles where potential non-compliance has been identified.

There are currently 95 vehicle models from 28 brands under investigation. Manufacturers with a vehicle model under investigation have received a notification of this. For legal and operational reasons, the DVSA does not publish case-specific figures during active investigations.