Unicorn could maintain aircraft, support fleet carriers, and inform the later light-fleet-carrier design, so she offered more utility per scarce prewar pound. The delayed end of the Ten Year Rule also encouraged policymakers to postpone smaller wartime escort programs. If officials did not expect war until the 1940s, a narrow emergency escort ship looked less urgent than a versatile aviation-support vessel. The choice therefore made sense within the assumptions and budget even though later events exposed the escort gap.
Chapter · 53:09-55:31
Why HMS Unicorn outranked an escort carrier
When extra funding appeared, the Royal Navy preferred Unicorn's aviation-support and carrier-development value to a narrower escort carrier.