Ford Mondeo: Diesel v petrol

Diesel best in top Mondeo

If you're buying a new car, choosing diesel won't automatically mean you'll save money.

Diesel cars tend to cost significantly more to buy than the same car with an equivalent size petrol engine.

For many cars, particularly small and medium cars, the extra money spent buying a diesel has begun to take longer to recoup through improved fuel consumption.

This has come about mainly through the extra cost of diesel at filling stations - prices at 12p per litre more than unleaded are typical at the time of writing.

Parker's has launched a calculator that works out whether it's worth choosing diesel over petrol, and it can be found at www.parkers.co.uk/cars/petrol-vs-diesel/.

For my Mondeo, the problem doesn't exist. The petrol equivalent to my 2.2 TDCi Titanium X Sport is the 2.5T Titanium X Sport.

The diesel version is only £146 more expensive to buy than the petrol version, and with an average of 45mpg versus 30mpg it takes a little more than 4000 miles before you start saving money - just two months' driving for me.

But it isn't this case for many family cars, so it's always worth making some calculations before you buy.

Current mileage: 10469

Average mpg: 47.7