CO2 Car Tax Rip Off

How would you like to pay your income tax based on a guess of how much the government think you will earn?
The new car tax rules mean that we will be paying our car tax based on a guess of how much CO2 our vehicles produce. Your car (if you have on) is given a value of grammes of CO2 per Kilometre and it is probably totally wrong.
My car says its CO2 is 202g/km but working it out over several tanks of petrol the worst case is 179g/km but because it says 202 I will be paying £300 for my car tax next year but it should be £205.

Here is how to work it out:- Divide 2.3 (a litre of petrol produces 2.3kg of CO2 or use 2.7 if you have a diesel car) by the number of kilometres you get from a litre of petrol. That figure will be 0.xxx the .xxx is the number of grammes you produce per km.

Now check your vehicle registration document and decide if the government is going to be ripping you off.

The new tax rates are here http://news.bbc.co.uk/1/hi/in_depth/629/629/7293011.stm