Everyone in this discussion seems to be forgetting Trident as well. There's a lot of assumption the next war will be helpfully similar to WW2, and some sort of reverse sweet spot where we are subject to naval interdiction but will not deploy the strategic nuclear deterrent, and at the same time have enough time to build things, but not things that require any of the rest of the supply chain than steel (I have bad news about the number of ASIC fabs in the UK).

Back to "dead men dominate UK politics". In this case, we're trying to refight a war from 70 years ago.

The absolute worst case is that it's not advantageous/useful at all in the next war to have the capability, but it wouldn't harm you at all if you do have it, it just wouldn't be useful. In every other case, from the worst case all the way up the continuum to the best case, having the capability is beneficial to varying levels of degree.

Well if trident gets used then what comes next is irrelevant.

It's like planning for your house burning down V dying. If you're dead you don't really need to worry about the after.

So yes the military plans for everyone but global thermo nuclear war, because there's no point planning for that anyway.

I wouldn't say were planning for the next ww2. Look at the number of tanks we have. If anything were over optimised for helping the US fight insurgencies in the middle east at the expense of being able to fight a high intensity war.

We follow a path governed only by the logic chain of previous mistakes. Our next recognition of one could be pretty brutal.