A P-8 type aircraft even in limited numbers for the UK I would see as essential if you want to maintain sovereignty on places like the Faulklands. In these troubled times one never knows when the next pimple of the a$re comes up or exactly where. A P-8 is deployable to almost anywhere not just around the coastline which can be left to smaller air vehicles. Even has in-flight refuelling if you fit a couple of booms to your tankers [or use someone else's]..