So it is nothing to do with the RN asking for a manpower uplift of 1500 - 2000 people before SDSR 15 (as did the RAF*), and it being accepted, but Cameron bottled it as it would have meant cutting Army numbers which would have looked bad?
If yes, then it is the Generals' mess.
I am sure that when
Albion and
Bulwark were designed, the assumption was made they would operate with a carrier for protection (Air Defence and ASW), Close Support of the troops, and lift.
This
old thread from 2003 suggests so.
*Where will the RAF find people to operate new MPA without causing pain elsewhere in the Service?