One of the most sensational runs for many years has been set up at Montlhéry by a normal ‘hard top’ Jaguar XK120. The idea originated in Leslie Johnson’s fertile brain, and as co-drivers he took a redoubtable trio — Stirling Moss, Jack Fairman and Bert Hadley.

Anyone who knows Montlhéry’s post-war surface will not be surprised to hear that after two days a rear spring broke. As a spare was not on the car no further international records could be attempted, for the rule is that such spares shall be carried on the car. Moreover, some four hours were lost replacing the spring, but the Jaguar contrived to conclude successfully what it had been set to do – it averaged 100.31mph for seven days and nights, covering in that time more than 16,851 miles. After which LWK 707 ran as well as it had at the start. This is a performance which will go down in motor history with Edge’s 24-hour run in 1907 and Lambert’s first ‘100 in the hour’ of 1913.

The greatest praise is due to all concerned, and especially to Johnson for sponsoring the attempt, Moss, Fairman and Hadley for so ably backing him up in his monotonous and dangerous bid, to Desmond Scannell, aided by Joan Scannell and ‘Mort’ Morris-Goodall, for managing the run and to Jaguar Cars for making such an astonishingly fast and durable standard closed carriage. On one occasion Johnson sat nine hours at the wheel, keeping up the average with the broken spring, refusing to involve his co-drivers in the added risk. The Jaguar ran on reliable Dunlop tyres (fitted by ‘Dunlop Mac’), breathed Shell fuel through SU carburettors (watched over by Leslie Kesterton), used Champion plugs, was arrested when required by Ferodo-lined Lockheed brakes, lubricated by Shell X-100 oil, greased by Tecalemit and had the fearful shocks from the track smoothed out by Girling dampers on the Salter springs.

Lucas electrical equipment stood up to all the big demands made of it, the Hardy Spicer propshaft and Salisbury gears gave no trouble, the engine was cooled by a Marston radiator, the drivers sat on Connolly upholstery, held a Bluemel steering wheel, watched Smith’s instruments and communicated effectively with the outer world via Pye radio checked over by K Custerton. The Jaguar mechanics Thompson, Sutton and Potter were present to service the car, and chief engineer Heynes adds another very large feather to a hat which is already overladen with plumage!

That the Jaguar took the following records lends additional merit: World’s and Class C 72 Hours (105.55mph), Class C 10,000 kilo (107.031mph), World’s and Class C four-day (101.17mph), World’s and Class C 15,000 kilo (101.94mph). The sheer speed of this XK120 on a mere 8 to 1 compression ratio was indicated early in the run, when Moss did a lap at 121.28mph, bumps notwithstanding. Formidable!