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Jaguar – The History & Mystery
of Mark Numbers

Article by: Hannah in General - 20 October

The Jaguar Mk2 makes frequent appearances in surveys of Britain’s favourite classics, largely thanks to a certain fictional TV detective from Oxford with a passion for opera and real ale, but try to fit it into the history of Jaguar’s system of assigning mark numbers to its vehicles and things can get a little confusing. Its predecessor was not known as the Mk1 until the Mk2 came along, it was contemporary with the MkX, the company seems to have been using a mixture of Arabic and Roman numerals in the naming of its vehicles – what exactly was going on?

Let’s go back to the start, and the founding of the Swallow Sidecar Company in 1922. Originally this was a partnership between William Lyons and William Walmsley making motorcycle sidecars, but they soon began developing passenger car bodies as well. In 1934 Lyons bought out Walmsley and, in order to do so, he formed S.S. Cars Ltd. In association with Standard Motor Co., S.S. then progressed to making complete cars and in 1935 they launched a 2.5 litre saloon with the model name Jaguar. The name was used as a model name for the next fourteen years.

Immediately after World War 2, in 1945, at the urging of owner William Lyons the board of S.S. Cars Ltd. agreed to change the name of the company to Jaguar Cars. Lyons rationale behind this was simple: the name S.S. had acquired unfortunate and terrible connotations during the war, whereas the name Jaguar was distinctive and had acquired a caché having been attached to a very successful series of cars noted for their speed, quality, reliability and cost-effectiveness. The change was made, but production of the Jaguar model inherited from S.S. Cars continued for another four years.

The company needed a new model, and from 1946 to 1948 William Lyons and his team built various prototypes with experimental chassis and bodies in their factory. Eventually they found the design that was right and put the car into production. However, strangely enough, the idea of calling it the Jaguar Jaguar didn’t hold much appeal. The new vehicle was named, therefore, the Jaguar Mark V, as it was the fifth of the prototypes that had been created by the renamed company. So, to clear up the first confusion, there had never been cars built and sold as Jaguars Mark I to IV. The Mark V’s predecessor did get given the name Mark IV, but only in retrospect to differentiate it from the new car. The company had never built anything as the Mark I, II or III.

Confusing? Well, Jaguar was not about to make things any easier because the successor to the Mark V was…the Mark VII. Yes, there was never truly a Mark VI. The company wanted to avoid confusion with the Bentley Mark VI, and although they did actually put one of their XK engines into a Mark V and designate it Mark VI, it is believed that only two of those cars were ever built. So the mark numbering system starts at V and moves straight on to VII. Happily, they did then make a Mark VIII (launched 1956), a Mark IX (launched 1958), and finally a Mark X (launched 1961). Having made the Mark X they appear to have decided that things were getting a little simple to understand, so they renamed it the 420G and followed it with the XJ6.

So much for the mark numbers in Roman numerals. But whilst all of that was going on, the company also made the Mark 1 and 2. Except they didn’t. Well, not really anyway. What they actually did in 1955 was to introduce a small saloon car to their range with two different engine sizes. They named it, simply, the Jaguar 2.4 litre or Jaguar 3.4 litre – no real model name, no mark number. Then, in 1959, the company decided to give that car a total revamp and the result was the Jaguar 2.4 or 3.4 litre…Mark 2. These vehicles did feature the badge ‘Mk2’ on the lower right corner of the boot lid, but it was only intended to differentiate the cars from the earlier small saloon model. Inevitably those earlier small saloons became known, retrospectively, as Mark 1s, but they were never badged or sold as that. The decision to use an Arabic numeral for the Mark 2 saloon was simply to avoid confusion with the mark numbers of the larger saloon range, which by now you will likely agree was a typically and lovably ‘Jaguar’ way of avoiding confusion!

So there we have the tangled history of Jaguar’s model numbers disentangled. If you own one of these cars, whichever it happens to be, here at Fiennes Classics and Fiennes Engineering you will find everything you need to restore it, maintain it, and keep it in perfect condition for years to come.