[will_critchlow]

"if motorists find their tax rising due to cheating by car manufacturers"

This doesn't require new enforcement or new taxes - a large part of the purchase price of petrol is tax.

[throwaway049]

In the UK we pay an annual tax [0] based on the engine size or CO2 emissions of the vehicle, in addition to tax on fuel. I doubt the government will move affected cars up the price bands post-purchase as it would be politically unpopular.

[0] https://www.gov.uk/calculate-vehicle-tax-rates