Sorry for the delay in replying.
First a correction - lots of Auxillary vessles are larger than SSBN's, I should have said they are the the largest
combat vessles after carriers and main amphibs.
Second Steph, you are talking about the purchase cost not the lifetime cost. The research costs and the logistics cost are far higher than the purchase costs.
The point of being able to afford more
Astute and
Queen Elizabeth's for the cost of a new generation is that economies of scale make purchasing and supporting a tenth
Astute a fraction the cost of researching, purchasing an supporting a new class of SSBN. Obviously the choice is not actually a choice between
Astute's and a new generation of SSBN's, but between
Astute's successor class or even the sucessor to that.
The economies of scale are particually pronounced at the SSN's scale. If we order 10-12 of a class (as opposed to the 6-8 we seem to be looking at) that basically means keeping a given drydock constantly producing SSN's. On the assumpion of a class-life (in terms of construction) of twenty years and approx two year construction time. Spares are also more economical for maintiaining more of the same class. Logistic chains already exist etc.
Most of the points you make about being able to nuke anywhere on earth at any moment I would agree with, as I said the capacity would become tatical rather than strategic. Obviously the ramifications of such a capacity remain strategic.
A cruise missile would be deployable from most naval assets, airbases, carriers and the auxilary vessles capable of re-fueling stvol aircraft. Obviously air-depoloyment would decrease the effective range of the missile since it would have to be launched from defencable airspace. We would no longer be able to nuke anywhere instantly, but we would retain the ability to nuke most hostile sites at short notice and the inability of an enemy to know
if we could nuke them or not.
Extending the range of a cruise missile to, say, 2k km would not be difficult. AFAIK, the key problems of using a cruise missile is that it is far easier to intercept than a sub-orbital missile. It is astonishingly hard to destroy something traveling at 30k mph. For a cruise missile to have the necessary ability to get through air defence it would have to be more stealthy and be hypersonic.
If we get scramjets working range would increase as they are far more fuel efficient in terms of distance traveled. If we get scrmjets working the speed would increase to at least mach 6, at which point existant air-defence would be basically worthless. Add increased stealth and the missile would not be as unstoppable as an SLBM, but it would not be too shabby either.
I say we dont need to be able to nuke anywhere on earth at zero notice. It is sufficient that any country that nuked us would loose a couple of dozen major cities. It makes the cost unacceptable for any potential agressor.
The piviotal issue is that the research and assets for my programme would be useful. A bunch of attack subs, a super-carrier, a cutting-edge cruise missile for use and export. Useful and lucrative by-products of the research, instead of duplicating research that all the nations we could export it to already have equivalents to. Clearly placing our deterrent in the hands of uncertain research is not tennable, however we have at least five years to kick off some viability studies, initial research etc. If it is not viable then, sure, lets build another gen of SSBN's, but we can afford to give the geeks five years and a billion quid.
Not that I have the slightest idea what I'm talking about
