The absence of a land-based area-air-defence missile system is the basis for a proposed home-defence role for a high-readiness Type 45. Earlier planning assumed an approaching threat would first encounter NATO forces or naval defences in the North Atlantic. A destroyer patrolling around Britain could add air-defence coverage and move toward a developing threat. It could also provide a separate readiness asset while a frigate concentrated on protecting the ballistic-missile-submarine force.
Chapter · 46:45-48:33
Type 45s could provide mobile homeland air defense
A proposed high-readiness Type 45 patrol would add mobile air defence around Britain while leaving a frigate available for deterrent protection.