Band A

This is the holy grail when it comes to road tax. Owners of cars that qualify for Band A pay precisely nothing. Yes, that’s right – zero! But at the moment only two models qualify: the Volkswagen Polo 1.4 TDI Bluemotion (above) and SEAT Ibiza ECOmotive (right) – which sits on the Polo platform and uses the same engine.

Neither car is particularly thrilling to drive, nor are they very quick. But you will be able to enjoy the smugness of knowing that you are paying exactly nothing to share the same road space as drivers who have had to fork out up to £400.

Thanks to new on-board software and a diesel particulate filter, emissions from the 79bhp powerplant are kept low at 99g/km of CO2. This also benefits economy, and both cars return an incredible 74.3mpg, meaning they cost peanuts to run. Other changes include a reduced kerbweight, aerodynamic tweaks and skinnier tyres. Compare them to the standard versions of both cars, which emit 119g/km of CO2, and the drop of 20g/km looks even more impressive. It also saves you £35 a year in the process.

The only other models to even come close to qualifying for Band A are the MINI Cooper D and Toyota Prius, at 104g/km. Considering the benefits of being able to offer a model that’s free to tax, it’s perhaps surprising that more car makers aren’t working to introduce models that emit less than 100g/km of CO2.

French giant PSA Peugeot Citroen was building a diesel hybrid with low emissions, but the programme has been shelved for the time being, as the costs of such a model would be too high. And while Smart makes a ForTwo diesel that would also qualify for free road tax, the firm doesn’t sell it here