So we were surprised to hear from Jaguar's famous former test driver Norman Dewis that he'd spent a long time back in 1975 testing a diesel. Very surprised.
The engine was supplied by Italian marine specialist VM Motori, who was looking to get into cars. Dewis tells us the engine was tested in an old Mark X, but would have been fitted to the highly acclaimed XJ6 (pictured top). "I went to the Nardo test track in Italy, we ran that Mark X and did 100,000 miles," he says.
He even got so far as to sign the engine off for production.
Of course it never made it into a Jaguar and Dewis has a great explanation as to why not. Jaguar founder William Lyons, obviously a bit more hands off at this point, comes up to Dewis one evening in the Browns Lane experimental shop and asks what he'd been up to. "I've been in Italy doing the diesel engine," he replies.
Then comes a legendary response from Lyons: "Diesel?! Diesel?! What are you talking about? We don't want a diesel engine in Jaguar cars. Dirty, smelly, noisy things - forget it!" As Dewis tells us, "All that work, blown away. He nearly sacked me for it."
Not that Dewis was really a fan, not back then. "Years ago diesel engines were crap - smelly, rattly, clonking," he says. "But now, now, I wouldn't go back to petrol." It helps he's got a new XF diesel of course, a fine car in both 2.2-litre and 3.0-litre guises.
It was under Ford stewardship that Jaguar got its first diesel, and Dewis is no fan of what happened then. "When Ford had Jaguar, it was diabolical - Ford should have never taken it on." Tried to make it too big, too fast, was his main criticism.
Now though, the man responsible for some of Jaguar's finest sports cars, including the D-Type and E-Type (of which more later) is happy with the current set-up under Indian owners Tata, especially with its hands-off approach to Jaguar's development. These days that means combining likes of the new (all-petrol) F-Type two-seater with the diesel saloons and estates preferred by the all-important business market.
As Dewis says, "I wonder what Lyons would say today?"