Let's face it none of us knows what the SDSR will bring. For too many years we (Kinloss) have been guilty of hiding behind the SSBN requirement, under the illusion that it was a cast iron reason to keep MPA.
Canada, New Zealand, South Korea, Japan, Norway, Italy, Spain, Portugal, India, Pakistan, Argentina, Nigeria, Turkey, Singapore, Indonesia, Ireland, Mexico, UAE, Algeria, Brazil, Chile, Poland, Iran, Sweden, Peru, Thailand, Australia, Germany, Greece, Taiwan, Israel, Denmark, Egypt, South Africa, Oman, etc. don't have SSBN but they all have MPA.
As has been mentioned before, we (Kinloss) have historically remained tight lipped about our roles (quite rightly), most onlookers assumed we just did ASW which kept us out of the spotlight and have taken this to mean we weren't/aren't doing anything else, hopefully this is being addressed at a level where it matters.
70% of the world is ocean, MPA is the most effective way to dominate it, oh and it also operates over the other 30%