Band C

With a wide 29g/km spread, Band C incorporates a huge line-up of cars, and accounts for the majority of new cars sold – nearly four million in 2006, the last year for which figures are available. A price hike from £35 to £120 means your tax bill jumps by £85 a year, but the choice ranges from the simple Perodua Kelisa to premium models, such as the BMW 520d.

As a result the bargain Perodua – at 121g/km – makes little sense from a tax point of view. If you opt for a car this basic and cheap, it’s obvious saving money is top of your motoring wish list. So forking out £120 a year for tax is going to sting – especially as there’s an army of talented budget options in Band B.

The same goes for the Proton Savvy (134g/km) and Fiat Panda 1.2 (133g/km) – engineering-wise it’s a poor show for such light, small cars to produce that much CO2. The Chevrolet Matiz, meanwhile, emits 136g/km – the same as the 520d. It’s clear evidence of how outdated the Chevy is, and the effectiveness of the German firm’s Efficient Dynamics system.

Stop-start technology and regenerative braking mean a host of BMWs have reduced emissions and fall into this bracket. All are powered by the same 2.0-litre diesel, and you can choose from a variety of models, including the 320d Touring and Coupé and even the new 120d Coupé, all at 128g/km.

Band C also includes the cleanest drop-tops. BMW’s new 120d Convertible emits only 134g/km, although if you want more room, the 320d cabrio just tips over into Band D. And the firm is not alone in giving wind-in-the-hair motoring with a £120 tax disc – the Vauxhall Tigra 1.3 CDTI pumps out 124g/km, while the Audi A3 Cabriolet emits 134 and 139g/km in 1.9 and 2.0-litre TDI guises.

If cabin space is a priority, there’s a host of models to choose from. The Ford Focus C-MAX puts out 127g/km in 1.6-litre TDCi trim. And if you want a bigger engine, how about the new Mondeo 1.8 TDCi ECOnetic, which emits 142g/km?

Thanks to slimmer tyres, improved aerodynamics and a retuned ECU, this green model drops into Band C, whereas the standard 1.8 TDCi emits 151g/km, so costs an extra £25 a year in Band D. Opt for the 2.5-litre petrol Mondeo estate, and you’d have to pay another £90 for your tax disc.

Other new models in Band C include the VW Golf Bluemotion (122g/km), Mercedes C200 CDI and Mazda 6 2.0D both 149g/km, while the Jaguar X-Type 2.0D just sneaks in, also with 149g/km.