Certain diesel cars have become less cost-effective to run and it can take driver’s decades to financially benefit. For years diesels have been a cheaper alternative as they typically provide more miles to the gallon. However a combination of higher leasing costs and with diesel now on average 12p more per litre than petrol, it can now take more than 25 years on certain models for drivers to see any financial benefit.

A BMW 318i ES 4door typically does 13 mpg more than BMWs petrol alternative; however you would have to do more than 250,000 miles in the diesel to see any financial benefit.

Parkers have created a diesel vs. petrol calculator; test it out by clicking here