My hon. Friend will know that some of the biggest challenges that lie ahead relate to constraining emissions in the transport sector. What are the prospects of achieving all-party consensus on the greater use of environmental taxation as a means of reducing transport emissions? Does he think that the basis exists for a consensus on a more progressive form of taxation to deal with gas-guzzling 4x4 vehicles, which would be hugely popular with the 95 per cent. of the population who do not drive 4x4s?