Why a British carrier fleet would probably buy Hawkeye

A small British fixed-wing AEW requirement would favor the proven E-2 Hawkeye, but carrier commonality could tempt later governments to misuse it as a cheaper land-based command aircraft.

Question

How would a successful British carrier AEW aircraft change later procurement?

Short answer

The Royal Navy would still probably adopt Hawkeye for cost and commonality, while the RAF would need a larger land-based system for theater command and control.

Notes

The P.138B counterfactual depends on Britain retaining carriers that can operate fixed-wing early-warning aircraft. A three-carrier CVA-01 force might embark four AEW aircraft per ship and buy about sixteen in total, making a separate British development hard to justify. The existing helicopter approach benefits from assigning a small number of airframes from a much larger ASW procurement, an economy unavailable to a tiny bespoke fixed-wing program. Buying Hawkeye alongside Phantom and later Hornet aircraft would offer another route to common systems. A separate concern is that a later government might try to replace land-based E-3 or E-7 capability with Hawkeye. The objection concerns the smaller operator team's workload and theater-command capacity, rather than simply the radar.