Polution not politics
If Ken or any other government body were at all serious about reducing emissions as opposed to raising extra monies to pay for their 2nd homes and surround sound flat screen TV's set ups, then they could not possibly justify the use of a CO2 output as a means to judge vehicles by.
The system is a complete farse CO2 is one of the LEAST damaging emissions emitted from a car, not to mention something that can be tackled with many innovative solutions. Why should companies such as Volvo (I'm a true petrolhead so anyone who knows anything about cars must know that I feel pretty pissed to be using them as a ref.) who's cars clean up the air as they drive through it due to particle filters in the radiator, a manufacturing company that has been truely doing their bit for the environment through every step of the supply chain, recycled this, sustainable that for decades already be penalised simply because there cars are heavy and require bigger engines and by default produce more CO2, however compare an S80 2.5 turbo to a Citroen Saxo 1.2 on every other aspect the Volvo is a far "greener" car (less sulphates, nitrates, and energy in the manufacturing process) but it would be subject to the higher taxes. In the meantime the fake green cars such as the Prius continue to be allowed to drive around the place for next to nothing.
I think the whole process of what is considered environmentally friendly needs properly evaluating as opposed to taking a pointless snapshot based a very weak scientific background.
If ken or anyone else is remotely serious about this then they need to look at the bigger picture.
So how about only allowing the government to use the road fund license and fuel duty to fix the roads and plan disruptions better as opposed to going into a giant black hole, only allowing so called green taxes to be used improving the environment, investing in microgeneration or new filtrate technologies (nanotubes are looking promising) but know all we do is sit back whilst the gov. half's their investments in science and engineering (see the recent physics cuts for a start) and what we have is a spiralling taxation system that will only spread and get worse like some form of cancer for the entire country.
Anyrate thats my two pence worth;.................