Updated: Oct 5, 2019
Here is recent correspondance i received from TFL with regard to the new ULEZ scheme for London road users
From the TFL website:
Minimum emission standards:
Petrol: Euro 4 Diesel: Euro 6
The ULEZ is enforced based on the declared emissions of the vehicle rather than the age. However:
Petrol cars that meet the ULEZ standards are generally those first registered with the DVLA after 2005, although cars that meet the standards have been available since 2001 Diesel cars that meet the standards are generally those first registered with the DVLA after September 2015
Nearly all petrol vehicles produced since 2005 meet the ULEZ standardsVehicles which meet the equivalent of the Euro 4 NOx standard for petrol have been available to buy since 2001
You can find a vehicle's Euro emission standard on its vehicle registration document.
From October 2021 the ULEZ will expand to the North and South Circular Roads. All cars within the expanded zone will need to meet the ULEZ emissions standards or pay a daily charge.