The Jaguar creation myth owes everything to this Autumn 1948 debutante.

In October 1948, a British industrialist stood nervously by as the assembled press and dignitaries gathered around the Jaguar stand at the Earls Court Motor show. On a plinth sat a metallic gold roadster of breathtaking simplicity and elegance of line. As the crowds gathered to swoon over the newly announced XK 120 Super Sports, Jaguar’s (as yet unknighted) William Lyons realised he might just have hit the big time.
Ah yes, creation myths. Usually a catalogue of unbridled success, but in Jaguar’s case, this was hardly the case. Because like most overnight successes, the XK 120’s was forged over some considerable time.
Creatives rarely enjoy being interrupted in their work. One easily loses one’s train of thought, the muse frequently escapes and it’s often difficult to find one’s way back. Conversely however, an interregnum can prove both fruitful and at times, necessary.
The Second World War however, as interruptions go, proved more challenging for William Lyons’ SS Cars than it did for most. Unlike many of his peers, Lyons had not done particularly well out of war-contract work, emerging from the hostilities as financially straitened as he went into them. In addition, owing to unpalatable connotations with Hitler’s notorious SS, he chose to re-brand as Jaguar Cars.
With most of Europe in ruins and those fortunate enough to have survived the onslaught piecing their lives and businesses together, chronic skills, power and material shortages and the inability to carry out much by way of research or development throughout hostilities ensured little new of note entered the marketplace in the immediate post-War era.

1948 however proved something of a watershed and XK 120’s rapturous introduction, alongside several other notable announcements that year, rendered all assembled numb with unrequited desire, with Jaguar becoming the focus of intense media and customer interest.
Like many works of genius, the XK 120 was something of a happy accident. Before the Blitz ground its destructive path through UK towns and cities, Lyons and his senior engineering staff had begun scheming the engineering basis and architecture for a new 100-mph saloon, but with war work preventing further development, they amused themselves with some ‘on the roof’ product planning while on firewatch duty at SS Cars’ Foleshill plant. During these sessions, the now illustrious XK engine’s specification was believed to have been fleshed out.
By 1948, the 3.4 litre DOHC six-cylinder XK engine and new bespoke chassis were complete, but Lyons had not finalised the new saloon’s body style, or obtained the necessary tooling, so in its stead, a heavily revised version of the pre-war SS-Jaguar saloon had been realised. The Mark V saloon, while retaining a good deal of its predecessor’s bodyshell, was fitted with the new chassis incorporating wishbone and torsion bar independent front suspension, but Lyons was aware that this alone would not be sufficient to ensure Jaguar received the level of visitor interest he required.
Taking a shortened and slightly narrower Mark V chassis, Lyons and his select band of highly gifted artisans began crafting a sinuous open roadster body. Through what would become a customary process of iterative trial, Lyons’ vision was translated from mind’s eye muse into hand-beaten aluminium. Taking his cue from the decadent streamliners of the previous decade and the Italian carrozzeiri-created Mille Miglia race cars for BMW et al, slowly, painstakingly, the 120’s lines were coaxed into being over a period of weeks during the run up to the Earls Court show.

The result was show-stoppingly beautiful and while it’s relatively easy to suggest that Lyons merely appropriated influences from other sources, his mastery of proportion, coupled with a level of detail restraint (which bordered on rectitude) ensured the XK 120 remains one of the most perfectly realised series production cars of all time and unarguably one of Lyons’ finest stylistic achievements.
Not only looking as fast as the wind in the autumn of 1948, the XK 120 proved its mettle, with UK weekly, Motor attaining a maximum of 124 mph in 1950 with a hood and sidescreens fitted. Later that year, a lightly tweaked version achieved over 132 mph at a specially timed run at Jabbeke in Belgium. The Autocar got hold of an example the same year, stating, “There is a temptation to draw from the motoring vocabulary every adjective in the superlative concerning the performance, and to call upon the devices of italics and even the capital letter.”
Undeniably quick in a straight line, arresting its speed came at greater cost, brake fade being the XK 120’s greatest bugbear. Early cars also handled with all the grace of an ocean-going yacht – the famous 1950 Daily Express race-winning cars heeling around corners with lurid bodyroll and abundant tyre squeal – matters remedied by stiffer front torsion bars, rear springs and dampers as fitted to post ’51 ‘Special Equipment’ models. Performance too gained a boost with revised cam profiles, a lighter flywheel and straight-through exhaust.

Jaguar was quite naturally unprepared for the onslaught which followed the XK 120’s launch. The first 240 bodies were handbuilt on an ash frame, and clad in alloy panels, before a partially tooled-up all-steel body came on stream in 1950. Built primarily for export, the XK 120 quickly became the darling of the Hollywood set, with film idols, Clark Gable and Humphrey Bogart being early devotees. 1951 saw the addition of the exquisite Fixed Head model, as perfect a stylistic homage to the late Jean Bugatti as has ever been cast in steel. A more luxurious Drophead model with a fully-lined roof was offered two years later, aimed at those who found the roadster too visceral a thrill.
Lyons was a master at conceptual realisations, but his restyling attempts often proved less creatively satisfying. Through its lengthy production run, the XK series was improved considerably, becoming faster, more civilised, better equipped, and more importantly, capable of arresting its own considerable performance courtesy of Dunlop disc brakes, but the successive XK iterations lost much of the 120’s visual delicacy.
However, with a total production run of over 30,500 cars, from 1949 through to 1961, the XK and the 120 in particular was a huge commercial and more significantly, reputational success for Jaguar. Indeed, it could be said without risk of hyperbole, that it singlehandedly put the Coventry carmaker on the map. It’s certainly quite impossible to imagine the marque’s subsequent success without it.

It is entirely possible however that without the war’s interruption, William Lyons may not have felt the need to build a sports model along such lines, so perhaps we ought to be grateful for its unwitting intervention. But conversely, the hostilities robbed us of six years of Lyons’ creative muse and at the very least delayed much of which would subsequently come to pass.
Without the XK120’s sex-appeal and Hollywood glamour however, Jaguar might never have made the impact in the US which would do so much to embed the leaping cat in American hearts, minds and fevered imaginations. Yes, interruptions do have their benefits.
This car design is just so amazing !
The MOMA has a Cisitalia and an E type convertible.
The Cisitalia looks dumpy compared to the 120.
It’s been said by so many people other than me, but Jaguar needs to get back to where it has a styling comparative advantage, and great performing (and sounding!) engines.
Like the XK120, people will overlook any number of faults if the engines and looks are great. (That was the Ferrari formula for many years as well.)
Something that looks like last year’s Hyundai and sounds like a 1970’s milk trolley isn’t going to excite anyone. And nothing like that is ever going to be featured in the MOMA.
MOMA is not just interested in looks speed or egotistical quests. MOMA has been showing cars in its garden since the early 1950s, but recent shows have looked at innovations not simply in style but in power plants, package, materials and marketing. The cars are not show-car prototypes, for the most part, but production or near-production models. Each explores a particular idea, from Chrysler’s CCV “China car,” a very simple model, evocative of the Citroen Deux Chevaux and designed for emerging nations, to the Fiat Multipla Bipolar, with dual gasoline and methane powerplant.
So yes there is every possibility that Jaguars current milk float,” as you label it” could appear in future as the beginning of high performance EVs taking the form of a more user (Human and environmental) friendly format.
The XK120 looks sublime in that high rear three-quarter photo. The double-curvature of the roof and simple inset of the rear window are just delightful; simple, but in no way bland. Modern car designers should take note.