Sheffield Forgemasters

Sheffield Forgemasters exists because a handful of components in a nuclear submarine cannot be bought anywhere else in Britain. The company melts its own steel, pours castings that run past 500 tonnes, forges under presses measured in thousands of tonnes, heat treats, machines and tests, all on one Sheffield site with a lineage running back to the eighteenth century iron trade. In July 2021 the Ministry of Defence bought the business outright for 2.56 million pounds, a price that reflected the balance sheet rather than the strategic value, and then committed to rebuilding it. Total committed MoD investment now stands at around 1.3 billion pounds, including 425 million announced in the 2025 spending review.

That money is going into physical capacity. A 13,000 tonne forging line is being installed, with the press itself shipped from Mitsubishi in Nagasaki, and a new machine shop of roughly 35,000 square metres is being built to house more than twenty heavy duty machine tools from Waldrich Siegen along with the cranage to move parts that weigh as much as a locomotive. The purpose is explicit. The UK needs a domestic source of large forgings and castings for the Dreadnought ballistic missile submarines now being built at Barrow and for SSN-AUKUS, the attack submarine class that will replace the Astute boats. Work on Astute components has run for years and gives the programme its track record.

Defence and marine is one of eight sectors the company sells into. Civil nuclear takes precision forged pressure boundary components for power generation. Offshore supplies oil and gas customers with heavy forged parts built for corrosive service. Power generation and renewables cover cast and forged steel for turbines, generators and hydropower. Ingot and bar sells semi finished product to other manufacturers. Steel plant supports multi ladle pours above 600 tonnes and machining of single components up to 350 tonnes. Steel processing makes forged rolls for industrial rolling mills, which is the oldest commercial line in the place. The company has also moved into gun barrel work, including large calibre barrel forgings and artillery barrel production alongside BAE Systems.

Around 750 people work there, selling into more than twenty five countries. Research effort has gone into electron beam welding for thick section joints, a process that cuts the time to build pressure vessels for compact reactors from months to a fraction of that, and into machining and inspection methods for parts too large to handle conventionally. For a supply chain manager the point is not breadth of catalogue. It is that a small number of critical, very large, very heavily specified steel components in the British defence programme come from this one site, and that the state now owns it for that reason. The commercial sectors are not incidental to that argument. Civil nuclear, offshore, power generation and rolling mill work keep the melt shop and the presses busy between defence orders, which is what makes the defence capacity affordable to hold in the first place, and it is the reason the company continues to sell heavily into export markets rather than working solely for its owner.