Could Britain manufacture 15-inch naval guns again?

Could Sheffield Forgemasters restart production of British 15-inch naval guns?

It is theoretically possible, but recreating the plant and tooling would be enormously expensive. Roughly twenty years is offered as a guess.

The particular Sheffield site is recalled as never having manufactured 15-inch guns, so establishing the capability there would mean starting from scratch. That recollection is qualified rather than presented as a checked manufacturing history. The work would include new facilities, heavy machinery and the tools needed to make other production tools. Roughly twenty years is suggested as an estimate of the effort involved. A follow-up challenges the picture of simply drilling through a solid block: heavy gun manufacture involved substantial hot forging and shaping as well as drilling. A Bethlehem Steel film is recommended as an example of the process.