Most economical diesel cars on sale in UK 2019

The most economical diesel cars promise stellar mpg figures and reduced harmful emissions. Here are the ten most efficient on sale now

Dominic Tobin
Feb 28, 2019

Diesel cars typically deliver better fuel economy than petrol vehicles, which is why they were seen as the greener choice for years.

But, with evidence that toxic emissions were often well-above legal limits in real-world driving, and news of manufacturers cheating emissions tests, diesel's reputation turned dirty.

Four years after the scandal emerged, things are different. New, stricter testing means that the latest vehicles must be as clean as petrol cars to be allowed on the roads, and a diesel engine generally remains more economical than an equivalent petrol version.

If you regularly travel long distances, a modern diesel car is likely to prove the most practical and efficient choice. It might not be as environmentally-friendly a choice as an electric car, but it doesn't require a lengthy recharging stop on a long trip.

Diesels can also be more economical than a petrol hybrid car, as these offer excellent fuel economy on shorter journeys, but are less effective over hundreds of motorway miles.

The most economical cars below are ranked according to miles per gallon (mpg) figures from a new, tougher fuel economy test known as WLTP. It doesn't fully replicate normal driving conditions, so it's also worth checking a vehicle's real-world fuel economy.

For the cleanest cars, choose one that's certified to Euro 6d or Euro 6d-Temp standards: these have been tested on the road to ensure that toxic emissions are within legal limits and include many cars sold in the past year.


Most economical diesel cars 2019


Economical diesel cars - need to know

Fuel economy
Recorded in miles per gallon (mpg), a car's official fuel economy figure is generated from a standard laboratory test, which every type of new car must go through. A new test, called WLTP, was introduced last year and has resulted in lower, more realistic figures, but they are still generally a bit higher than you'll see in real-world driving.

CO2 emissions
Cars are tested for the amount of carbon dioxide (CO2) produced in an aevrage kilometre of driving (g/km). Diesel cars generally produce less than an equivalent petrol model. Low CO2 figures can reduce your car tax (less so for cars first sold after April 2017) and company car tax, although diesel vehicles carry a company car tax surcharge.

Euro 6 emissions
Since September 2015, new cars have had to comply with Euro 6 emissions standards. These vehicles are exempt from inner-city pollution charges, including London's ultra low emission zone (ULEZ) and other clean air zones. The latest cars are tested to a tougher Euro 6d or Euro 6d-Temp standard, where emissions are tested in real-world conditions.

Britain's most economical new cars 2019 

1. Mercedes E-Class

Latest Mercedes E-Class diesel deals from £13,499
Finance from £212 per month  
Mercedes E 300 de 201.8mpg / 41g/km CO2

Sitting at the top of the list by virtue of it being one of the few diesel plug-in hybrid cars in Britain, the new Mercedes E 300 de is by far the most efficient diesel car on sale now, with a stratospheric 201.8mpg official fuel economy figure and meagre 41g/km CO2 emissions.

As with any plug-in hybrid, the actual fuel consumpton will depend on how the car is used. On short journeys, the diesel engine will rarely switch on, as the car's large battery can power it for up to ??? miles when the battery is fully charged. On longer trips, however, the diesel engine will be used for most of the time, so the mpg figures may be little diffeent to a standard diesel.

The car has only just been launched, so is not yet available as a used model. There are plenty of efficient second-hand Mercedes E-Class diesel cars to choose from.


2. Peugeot 208

Latest Peugeot 208 diesel deals from £5,600
Finance from £89 per month 

Peugeot 208 1.5 BlueHDi 100 67.7mpg / 95g/km CO2


3. Ford Focus

Latest Ford Focus diesel deals from £7,399
Finance from £121 per month 

Ford Focus 1.5 EcoBlue 95PS 64.2mpg / 91g/km CO2


4. Citroen C3 Aircross

Latest Citroen C3 Aircross diesel deals from £12,750
Finance from £198 per month 

Citroen C3 Aircross BlueHDi 100 63.1mpg / 103g/km CO2


5. Honda Civic

Latest Honda Civic diesel deals from £7,495
Finance from £127 per month 

Honda Civic 1.6 i-DTEC 62.8mpg / 93g/km CO2


6. Renault Megane

Latest Honda Civic diesel deals from £5,799
Finance from £106 per month 

Renault Megane dCi 115 62.8mpg / 101g/km CO2


7. DS 3 Crossback

DS 3 Crossback BlueHDi 100 62.7mpg / 97g/km CO2
New car list price from Latest offers


8. Dacia Sandero

Latest Dacia Sandero diesel deals from £4,990
Finance from £82 per month 

Dacia Sandero Blue dCi 95 62.7mpg / 98g/km CO2


9. Mercedes A-Class

Latest Mercedes A-Class diesel deals from £9,950
Finance from £145 per month 

Mercedes A 180 d 61.4mpg / 108g/km CO2


10. Mercedes C-Class

Latest Mercedes C-Class diesel deals from £12,000
Finance from £165 per month 

Mercedes C 200 d 61.4mpg / 108g/km CO2


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