March is one of two times in a year when UK number plates change – and it’s by far the most popular month for new car sales. However, registrations of diesel vehicles plummeted by 30% in 2018 as a result of environmental concerns and tax changes, so now there’s a renewed emphasis on petrol cars.

They may not be as economical as diesels on longer runs, but the gap is closing, so if you’re looking to buy a new 19-plate petrol-powered car from March 1, we’ve come up with a selection of 25 of the most frugal and affordable.

Most are small city cars and superminis, but we’ve also added a couple of family-sized hatchbacks to demonstrate that larger cars with punchy little three-cylinder 1.0-litre turbo units are surprisingly good.

All figures quoted are from manufacturers’ own websites and use the new Worldwide Harmonised Light Vehicle Test Procedure (WLTP) which is meant to give motorists a more realistic idea of fuel economy.