"Currently the RN has 2 Aircraft Carriers. 1 LPH, 2 or 3 Type 45 Destroyers, 5 Type 42 Destroyers, 13 Type 23 Frigates, 4 Type 22 Frigates, 2 LPD's, 8 SSN's, 4 SSBN's 16 MCM's ships, plus assorted patrol vessels, etc. Plus the RFA with about a further 16 ships including some Amphibious vessels.
The 5 Type 42 Destroyers will not last much longer, with or without the Queen Elizabeth Class Aircraft Carriers. Same goes for the LPH, HMS Ocean. The 4 Type 22 Frigates are still good ships and should be kept, but probably will not be. And, of course, in due course, the QE's will replace the Invincible's. (just as the Type 45's are replacing the Type 42's, although it is a pity the RN is not getting at least eight rather than only six) So that is 8-12 ships that will go that any scribbler can attempt to make something of, when in fact they are, mostly, time expired ships.
With the Queen Elizabeth class Aircraft Carriers, new escorts will come, in time.
The only Frigate cuts I see as likely are the four remaining Type 22's. A pity as they are still very good ships, but they require relatively large crews, which is the main point against them. The Type 23's remain perhaps the worlds premier ASW ships.
It would be much easier to regenerate escort numbers than, once you have lost it completely, to regenerate Carrier Air.
For full war fighting a Carrier Task Group will need three - four Type 23 Frigates and one - Two Type 45 Destroyers plus an SSN or two. An Amphibious Task group will need something like the same surface escorts. Thus, providing the Government don't cut the Amphibs too much, the RN will, just, have the ships it needs to generate both a Carrier Task Group and an Amphibious Task Group in any kind of emergency.
A few years down the line we might well see half a dozen or so 'general purpose' type Frigates, suitable for many of the day to day Naval tasks, such ships need not be very expensive. Further down the track the Type 23's will have to be replaced.
If the RN comes out of this round of Defence cuts with a balanced force, including Carrier Air, that's a win for the RN, for the British Armed Forces generally and for UK."