Jaguar Land Rover (JLR) boss Ralf Speth has launched a fierce defence of diesel cars and attacked the demonisation of modern diesel engines, which he believes to be incorrect.

Speth told Autocar that his company would be doing more to promote modern diesel technology, and said that its continued adoption would be crucial if the industry was to meet the every stricter emissions legislation imposed upon it.

“The latest diesel technology is really such a step in emissions, performance, particulates; it’s better for the environment when compared to [an equivalent] petrol. Diesel has to – needs to – have a future.”

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Speth believes that the issue of diesel emissions is one for the entire transport and automotive industry, not just one related to cars, as diesel is the effectively the sole power source used for commercial vehicles, lorries, buses and taxis, all of which are big contributors to air pollution, particularly in major cities, saying: "the complete automotive industry needs diesel to fulfil legislative requirements”.

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Speth highlighted the distinction between older diesels and newer ones, with modern diesels being much cleaner and meeting current legislation. Reporting on diesel has lumped the technology old and new together as a whole, he believes, and has led to the demonisation of the technology as a whole, which Speth believes to be incorrect.

“Anyone can see the black smoke coming out of old diesels is bad. We need to replace them with newer ones.”

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Speth said the cleaner emissions of modern diesels is the important bridging technology in ensuring emissions continue to fall before hybrids and electric cars really hit the mainstream. Widespread adoption of hybrid and electric cars is needed for the industry to meet stricter legislative emissions targets, but the industry was instead seeing a shift back towards petrols.

“It’s bad for the industry, bad for Jaguar Land Rover, and bad for Europe,” he said. The last point is key, as Speth said that the European car industry more than anywhere else in the world is reliant on diesel cars, and moves away from them would impact the continent’s ability to meet targets.

Speth hinted that he believed the start of the demonisation against diesel can be traced back to the Volkswagen Dieselgate emissions scandal, on which he said: “This kind of manipulation software is not acceptable. Unfortunately, the whole automotive industry suffers, not just Volkswagen.”