His involvement began when the first prototypes were built, and the first step was to sort out the basic handling on the steering pad at the MIRA test grounds. ‘I always tried to get neutral steer, with the back end breaking away first so you could control it on the throttle,’ says Dewis. ‘I had my standards – I knew what I wanted and if it didn’t meet the standard I wouldn’t sign it off. No prototype ever gets through any of the test procedures first time.’
In the Seventies Dewis managed a team of five test engineers and a dozen drivers. New recruits were bedded in on the rough Belgian pavé test. ‘You could only do probably an hour at 30mph before your stomach started to ache and you had to have a rest,’ Dewis chuckles. ‘We’d do 1000 miles on it for each car we tested.’
You only need a short stretch of fast road to understand why the XJ made such a huge impact on the luxury car market 50 years ago. We’re driving this 2.8-litre variant – the first XJ6 to be road-registered and the oldest surviving example of the breed, no less – and the refinement is extraordinary. The delicious six-cylinder timbre is well muted, road noise from what were considered large tyres at the time is miniscule and there’s only the slightest wind rustle from the A-pillars. You can imagine executives from Mercedes-Benz or Rolls-Royce having their first ride in an XJ in 1968 and looking nervously at each other, all thinking the same things – a) How the hell did Lyons do this? And b) We need to make a better car.