Question to the HM Treasury:

To ask Mr Chancellor of the Exchequer, for what reasons private cars that have been converted to LPG only receive a discount on Vehicle Excise Duty instead of being reclassified according to their new carbon dioxide emissions rating.

The government estimates that the cost of a formal laboratory test to recertify carbon dioxide (CO₂) emission values for converted vehicles is in many cases greater than the lifetime VED savings that would be due to the motorist for that vehicle. It is therefore impractical to conduct such tests on a widespread basis.

Instead the government offers a £10 discount to VED rates for any vehicle that has been converted to use LPG, without the need for formal laboratory retesting.

Vehicles using LPG also benefit from reduced fuel duty costs relative to petrol and diesel.