Catapults, Costs and Carrier Capacity
So RN looks like it'll be the only major customer for a non-standard SVTOL variant of the F35. Read: cost over-run, multiplied.
Cat-launched variant much cheaper, due to much larger USN order bringing down up-front unit costs and whole-life overhead.
Redesigning UK carriers to accommodate cats would, Navy blokes say, involve installation of a steam system the size of a Leander Class frigate's propulsion gear – and that's just for the catapults, the gas turbine system would still handle the carrier's propulsion.
Which means less space to carry aircraft. Which kinda misses the point of an Aircraft Carrier.
So a redesign to nuclear would provide (a la USN) more than adequate power for both propulsion and cat launch, along with all the other benefits of greater operational flexibility. (And that's a big plus).
Using nuclear for electrical drive of maglev catapults, not inefficiently piping steam all over the shop for a WW2-style plane-pinger, would both save both space and increase Aircraft Carrying Capacity (a double plus). USN is already trialling maglev cats at Lakehurst.
And that's in addition to being able to use all that space currently designed for intakes and funnels for increased Aircraft Carrying Capacity (a triple plus).
And the buckling deck problem goes away (a quadruple plus).
And patrol fighters can land with a full warload, without having to ditch unused munitions (a quintuple plus).
"HMS Eric Laithwaite", anybody? A cost-effective, highly efficient and operationally robust maglev-toting British carrier with worldwide capability. Now there's a thought.