Why stripped-down frigates are poor fishery-protection ships

Could stripped-down Type 23 frigates be retained for fisheries protection?

No. They would cost far more to run than cutters or offshore patrol vessels, while the Navy needs its escorts for higher-priority roles.

Even a reduced Type 23 would be an expensive answer to a constabulary mission. Border Force cutters and River-class offshore patrol vessels can cover the task more cheaply, while the Royal Navy's small escort force is needed for overseas and warfighting duties. Much domestic constabulary funding sits with the Home Office and Border Force rather than the Navy. Additional OPVs would offer a cheaper way to expand fisheries protection and provide useful junior-command training. Removing equipment does not remove the cost of operating a complex frigate hull and crew.