The MPs spend so much time in London that they forget the rest of the country needs cars to do ordinary things. Move parliament to any place other than London and they'd understand why most of us like to have a nice car.
Having said that, I agree that they should be incentivising manufacturers to reduce emissions and I believe that as they do it, car performance will still improve due to improvements in technology.
Its a tough one, I want all you gaz guzzling ba5tards to think about the environment but I want to pootle about in my car that gives off 284g/km CO2