I've had a look at the website:
It seems that the new VED Band G (CO2 >226 g/km) only applies to new cars registered after 23 March 2006. This means that those of you who already own a motorised shed/Chelsea Tractor shouldn't have to pay the £45 increase.
However, there is also band F (CO2 186 to 225 g/km) that has increased by £25 (didn't hear that mentioned in the budget speech). This increase will catch a lot more vehicles around the 2 litre+ engine size.
So, if you have a vehicle registered before 23 March 2006 that produces CO2 >226 g/km, where does that leave you? You will be outside of Band F (which cuts off at CO2 225g/km), but not caught by Band G because your vehicle is not registered after 23 March 2006.
From the website:
Vehicle excise duty (VED)
To further strengthen environmental incentives, the Government announces the introduction of a new higher band of Graduated VED (band G) for the most polluting new vehicles (those above 225g of CO2 per kilometre) registered after 22 March 2006, set at £210 for petrol cars, and the reduction of the VED rates for small number if cars with the very lowest carbon emission (band A) to £0 to assist the development of the low carbon car market.
VED rates will also be reduced for bands B and C by £35 and £5; frozen for bands D and E; and increased by £25 for band F. Rates for pre-2001 registered cars and light goods vehicles in the lower band will be frozen with the higher band increased by £5.
Fifty per cent of vehicles will see their VED frozen or reduced.
Graduated VED for Private Vehicles (registered from March 2001):
Band CO2 (g/km) Change Petrol Diesel A 100 & below -£65 £0 £0 B 101 to 120 -£35 £40 £50 C 121 to 150 -£5 £100 £110 D 151 to 165 0 £125 £135 E 166 to 185 0 £150 £160 F 186 to 225 +£25 £190 £195 G* 226 & above +£45 £210 £215
*for new cars registered after 23 March 2006Clear as mud legislation, as usual!