Note that I mentioned, keeping the US aside.
I concur with everything else here. But you are commenting from a geo-strategic POV, whereas whatever I wrote was from a strictly stand-alone militaristic locus.
The Diego Garcia lease is getting over by 2016 with an ongoing legal battle already in place for the return of about 5000 indegenuous people, illegaly uprooted from their ancestral archipelago. Further, under the US-UK treaty, the base (island) is leased to the US for a period of fifty years ending in 2016. This can be renewed on an ad hoc basis as needed for the defense of both nations.
Given that the US considers Diego Garcia one of its most strategically important pieces of real estate coupled with the current issues in the Middle East, it is highly likely that the land lease will be extended indefinitely. This in essence negates any near term chance of the RN eastablishing any meaningful individual/cooperative presence in Diego Garcia.
Chunder,You probably wouldn't need a carrier for that....
Look at the co-ordinates 50 Years or more down the line and tell me, which other country would need carriers and a lot of them for that?