Re: Worth it?
For about 40 minutes at which point the ICBMs would make the whole thing rather irrelevant.
I'm sorry, my Welsh compatriot, but you clearly understand nothing of the principles of deterrence.If I can offer you a cheap and vaguely adequate precis:
Nobody launches ICBM in the first instance, and nobody goes nuclear over (eg) the sinking of a single naval vessel. So, starting from any small attack, anybody with nuclear pretensions need to be able to escalate at that (and every subsequent) level, so that they win each round unless the enemy escalate. If you can in principle keep that going until the prospect is Armageddon, then no sane enemy will attack as there's no victory.
To avoid the end of the world, we need to have an escalating tactical response at each level. Imagine a conflict with France. We start off with words. Then we accidentally sink a French trawler. They sink a British fisheries vessel. We torpedo a French corvette. They take out one of our frigates, we attack their carrier, they attack ours, and so forth...but the point of deterrence is that by having the weapons to do so, each "next step" is a feasible response.
That's why your comment about stopping buying arms from the US is nonsense, because it only through the possession of the escalatory weaponry that possession of a nuclear capability make sense. Buying the F35B is without doubt a waste of money as any form of tactical asset - but having invoked the ICBM argument you've shown the single reason why it could make some sense. As it happens, the UK is currently devoid of an important military asset in tactical nuclear weapons - the sort of thing to take out a tank division or a naval battlegroup. But with only one weak link in the chain, would you take the chance of starting a war with the UK?