If you are looking for a petrol car with the lowest possible road tax, your best bet is a pre-April 2017 model with very low CO2 emissions. Several small petrol and mild-hybrid cars fall into Band A (0 g/km, £0 tax) or Band B (1 to 50 g/km, £10 per year). Here are the standout choices:
For post-2017 petrol cars, the first-year tax varies (a car producing 91 to 100 g/km pays £135 in year one), but from year two the standard £190 flat rate applies to all. The main way to save on a newer petrol car is to avoid models with a list price above £40,000.
Check the full running costs for any of these models. The Toyota Yaris and Ford Fiesta are consistently among the cheapest cars to run overall.