 The origin of the Mark V name, always printed in company documents as a Roman numeral V, never an Arabic number 5, is somewhat mysterious as there had been no Mk I to IV Jaguars and the MK IV designation was only given to its predecessor after the launch of the Mark V.

Chairman and chief stylist William Lyons (Sir William after 1956) and his team of body-shop assistants known as panel beaters put together five prototype bodies with various chassis experiments in the 1946-1948 period before he was satisfied with the result, and the chosen one was known as Mark V in internal documents.Lyons explained this in a speech given on 30 September 1948 to introduce the new car to distributors and members of the press, so that is how the Mark V got its name.A photograph of the discarded prototypes survives with the Jaguar Daimler Heritage Trust.