If there is a large war, those countries will prioritize domestic consumption and the UK will immediately stop being able to produce weapons.

Domestic steel production is an essential element of being sovereign, as opposed to being the handpuppet of a larger power (like the US).

Now check where the inputs to steel production come from.

The UK built a lot of refining to use local iron ore and coal deposits. It used those deposits. They are now substantially used up. Subsurface mining is uneconomic, and open mining is politically unthinkable.

There is actually a really high quality government review of the whole subject: https://assets.publishing.service.gov.uk/media/690b868714b04...

Lots of discussion of moving to EAF/DRI from traditional blast furnaces.

I don't see how the UK could generally be self-sufficient in any large war.

> If there is a large war, those countries will prioritize domestic consumption and the UK will immediately stop being able to produce weapons.

Same with the iron we'd need to make our own steel.

And a current glut just makes it even cheaper for us to stockpile, vs spending on votes by propping up a failing industry.

> Domestic steel production is an essential element of being sovereign, as opposed to being the handpuppet of a larger power (like the US).

How did self-sufficiency shake out for Europe as a whole during WWII?

Really? There is a large war going on right now and the key material is chips. Drone don't use a lot of steel, neither do missiles or modern airplanes.

Yes you need artillery and particularly shells. But you are so much more limited by the capacity of your munition factories that how much steel you have would not be an issue. One of the main things you would need for a new munitions factory is trained workers.

The World Wars were wars of mass mobilization and industrial capacity. People went into the first thinking cavalry was important, the second thinking battleships still mattered. My point is I have no idea what the next great war might be like, but thinking the winner will be who chugs out the most tanks in five years may be looking in the rear view mirror.