Much as it pains a former 'Gentleman in Khaki' the number 1, national survival, military task is the security of the seas around and sea lanes to and from the UK.
It surprises me that the current River class OPV doesn't have even a limited ASW capability (no embarked Helicopter or ASW weapons) so that it could be pressed into escort duty.
Separately, but related, in the new order we are going to have our own independent fisheries policy and have to police it. To do that will need a layered capability of MPA and patrol vessels.
One query I have is whether the maritime patrol task is not one suited to an all weather long endurance RPV? If you stopped dragging the crew around you could carry more fuel and mission stores n'est ce pas?
I am not so worried about merchant fleet tonnage as the drop in registered tonnage, in part, is just a reflection of the commercial benefits of regisitering what would in previous times have been a 'British' ship in cheaper overseas registers.
EG