Brit carrier(s) at Midway
A quick bit of googling shows that the Vic was in the Mediterranean but the Illustrious, Formidable and their half-sister Indomitable were all in the Indian Ocean between April and August 1942. I think with HMS Warspite and presumably some cruisers and destroyers as escorts. They were mainly involved in seizing Madagascar from Vichy France so that the island's ports couldn't be used by Japanese raiders.
So, it seems that one at least could in theory have been spared along with an escort to go via Sydney to Pearl Harbour. How long under combat conditions would that voyage take, skirting the strike radius of Japanese air bases?
The air group I've found for HMS Illustrious in September 1942 was 21 Martlet (F-4F I think, comparable to US Wildcat), 6 Fulmar and 18 Swordfish TSR - useful for scouting and AS work only I guess. Or night strike? Able to defend itself and help a companion carrier if not add much to the strike force. Saving Yorktown I presume would count as making a valuable difference to the outcome but the glory would still belong to the USN.
Of course, if all
three were sent...
Sadly, I suspect that big a force couldn't have been supplied by the RN at such a distance from its bases, nor easily by the USN at the time. Still, by arriving in the combat area from a different angle to the US fleet, it would have complicated the IJN's operations. I doubt if an even more convincing victory could have been won though and there's the risk the Japanese would simply have concluded the odds were too high and abandoned the operation. Of course, alternatively the IJN could have attacked the RN carriers* after mistaking them for the US forces. Thus leaving themselves open to a devastating US strike! Not sure the role of sacrificial pawns would have been appreciated in Britain though.
Worth gaming out?? Anyone got a better game than the old SPI
Fast Carriers?
* How well they could survive a full-scale strike is unclear. The armour would help and the fighter direction was good. Provided they avoided torpedo strikes i think it likely they would have survived hits from bombs. Moreover, the Indomitable did get torpedoed and survived.