TODAY'S diesels are around a quarter more fuel efficient than those built just 10 years ago thanks to improvements in engine technology.
The increasing number of diesel cars fitted with components such as common-rail diesel and Start-Stop have benefited from significantly reduced emissions and lower running costs.
According to the Society of Motor Manufacturers and Traders' New Car CO2 Report, new diesels are 21 per cent less polluting and 27 per cent more economical than they were in 2003. Ten years ago, the average annual fuel bill for 12,000 miles of driving was £1,690, today it is £1,330.
Diesels have improved in leaps and bounds in performance, efficiency and refinement.
One of the first major steps was the introduction of turbochargers in the 1980s.
The next major change was the common-rail system, pioneered by Bosch, which injected fuel into the engine at a higher pressure. The first car to use this was the Alfa Romeo 156 2.4 JTD in 1997.
Further developments of this technology alone has reduced emissions by up to 20 per cent.
One of Bosch's latest milestone innovations was the introduction of Start-Stop in 2007, which turns the engine off automatically when the car comes to a stop, starting it again when the car drives off.
Today, Start-Stop is fitted to every other new car manufactured in Western Europe.
It helps to reduce their emissions by up to eight per cent, saving the average driver more than £100 per year.