3. Hyundai i20 1.1 CRDi Blue - most economical cars

The Hyundai i20 is the sister car to the Kia Rio, and is one of the most economical cars in its class. It uses the same 1.1-litre three-cylinder diesel engine with 74bhp, and has almost identical efficiency stats. Economy is the same at 88.3mpg, but the Hyundai emits 84g/km CO2 compared to the Kia’s 85g/km.

It has a low insurance group rating, which also helps to keep costs down, and a generous five-year warranty – giving you peace of mind that should anything go wrong, you won’t have to foot the bill to put it right.

It’s also spacious. It will comfortably seat three adults in the back and the boot is 295 litres – more than the Kia Rio, Ford Fiesta and Volkswagen Polo. It expands to a huge 1,060 litres with the rear seats folded, too.

The i20 isn’t the most exciting car to drive – but driver involvement isn’t exactly a key quality in an eco car, and the i20 has other strengths. It has a very comfortable ride, for starters, but it’s also very refined. Even the three-cylinder diesel engine is quiet and well behaved.