Nah,
that's an even more crackpot idea than most - even the RN, were they determined to do the RAF down, would not pull the rug from under their own feet with no possibility of producing an RN replacement in the immediate future.
If the RN were given a big pot of gold right now, today, and the go ahead to do what they wanted, then it'd still take them a considerable time to embark an ASW fixed wing asset with all the skills needed to actually do the job. Should the RN think differently, then boy oh boy have they got a surprise coming.
You can make a conspiracy theory about just about anything (notice how Col Ghadaffi and Bruce Forsyth are never on TV at the same time?) but to produce one with legs there has to be some semblance of reality to it at some point. 'RN torpedoes Nimrod because they secretly want into the MPA game' doesn't ring true.
I would suggest that the powers that be in the RN aren't actually bothered about aircraft at all - but they DO want big boats, and since about 1942 the big boat that gives admirals bragging rights is the attack carrier. The RN hierarchy want carriers - no doubt about it - but that doesn't mean they necessarily give a stuff about having aircraft for anything beyond decorative purposes.
Dave