Sorry guys but either the author does not understand deterrence, or I don't! Assuming Russia is the prime threat, surely they say, "do as we say or Brum (or other large city) is flattened". We say no, they launch and we try and send some F35s to retaliate. The carrier has a Russian SSN in tow (crikey knows where it would need to be to raid St Petersburg,but not anywhere safe) and every RAF tanker is well and truly marked. Likely outcome is we can't afford the risk and we agree to the Russian demand. Deterrent failed!
So this only really works for roque now nuclear states that acquire longer range rockets. Is that really what we intend the deterrent to provide?
The core thing is do we spend money on successor, or go without and trust the USA to look out for us. (Like Italy, Germany, Spain etc) They are the only sensible choices. And if we choose to go without, the money is more likely to go away from defence. When we spend £50 billion a year on interest, it would be wrong to spend money just because we cut a programme.
My belief is we are a much safer nation with the deterrent. However, whether we can afford a replacement is a real question that needs an answer. Spending money on a watered down non-effective alternative is a nonsense.
The only other route I see is agreeing with the USA that we provide a core non nuclear capability they rely upon, in return for providing our cover. This may hold some water as their Ohio replacement costs really do make the eyes water!