Now there's proof that Jaguar's new 2.2-litre four-cylinder diesel model is the most efficient Jaguar ever produced - thanks to a lengthly road trip.
The journey began at the factory in which it was created at Castle Bromwich in Birmingham and stretched 1313km to Munich on a single tank of diesel.
Driven by independent tester David Madgwick, navigated by Alexander Madgwick, the scrupulously standard XF passed through four countries taking in a mix of winding country roads, highways and dense urban traffic.
The XF, with just over 4800km on the clock at the point of departure, consumed just 64 litres of fuel to average 5.0 litres per 100km.
Despite its focus on efficiency, the XF 2.2 produces 140kW and 450Nm, allowing a claimed 0-100km/h sprint in just 8.5-seconds.
The new 2.2-litre oil burner is linked to an eight-speed ZF automatic gearbox and an idle-stop system.