Originally Posted by
megan
Anorak here. By rights the F-35 should be the Lightning IV. The very first Lightning was the P-38, though an American aircraft the name was bestowed by the British, in British service to be known as "Lightning Mark I", and a one off P-38, "Lightning Mark II". For the US the F-35 is indeed a Lightning II, as they never enjoyed
newt's Lightning Mk. III except by way of exchange.
Wouldn’t it be [Name][Role/s].Mk[x] in modern RAF/RN use? By incorporating the WW2 P-38, your example mixes two naming conventions; the early WW2 type/name + iteration (e.g. “Spitfire Mk.IIa”) with more modern type/name + role/s. Just deriving conventions here, going from “Phantom FG.1” or “Tornado GR.1” and similar. As this is both a new aircraft type with its own role/s, “Lightning GR.1” or similar would seem fit the logic. Between the UK and the US, only the latter seems to incorporate numbers into the aircraft name, not the role/designator (e.g. C-17A Globemaster III).