GRAND DESIGNS

THERE’S A lot of focus on the E-type this year as Jaguar’s iconic sports car celebrates its 60th birthday, but it wasn’t the only massively influential Jaguar to make its debut in 1961. For while the E-type was grabbing all the performance headlines, another Jaguar, the Mk X, was busily innovating in a very different way.

We have put one of the last Mk X variants – a 1970 420G, owned by Jaguar Heritage – together with an X350 XJ6 to compare the two cars, each of which bookend an era of Jaguar styling that encapsulates more than four decades of the low-roof, quad-headlamp look that defined Jaguar saloons for several generations.

It started with the Mk X – or Project Zenith, as it was known internally throughout its gestation. The all-new large Jaguar saloon was planned to replace the Mk IX, which was a traditional steel-framed car built on separate chassis. The new model would instead employ the unitary construction build methods developed by Jaguar for the 2.4 saloon of 1955, but in a substantially larger package.

The Mk X would define