My hon. Friend has a point, but the point made by hon. Friend the Member for Devon, North was that in Minnesota there is quite widespread use of CNG.. I understand that the tax on petrol in the United States is much lower than it is here. Therefore, one cannot necessarily say that in the United States there is an incentive to use CNG which does not exist here. Due to the higher petrol taxation in this country, one might expect there to be greater incentive to use CNG.

This is a welcome debate, and I am grateful to my hon. Friend the Member for Devon, North for his positive contribution to it. Improvements in the efficiency of conventional vehicles, which constitute the vast majority of the fleet, still offer the greatest potential benefits in helping to limit CO₂ and other emissions from road transport. We wish to encourage the development of vehicles powered by currently unconventional sources of energy. We see some long-term potential for CNG vehicles in our continuing efforts to improve the environment.

Question put and agreed to.

Adjourned accordingly at eleven minutes past Eleven o'clock.