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.