The plant opened in 1971 and produced steel via the Electric Arc Furnace (EAF) method rather than as a primary metal by the smelting of iron ore.

[1] The steelworks was constructed on the site of a former dockyard,[note 1][2] military port and hospital in Sheerness, Isle of Sheppey, Kent in 1971.

[5] The Sheerness site made steel from scrap metal using the EAF method with scrap metal as opposed to the normal route which was to smelt iron ore and carbon in a Basic oxygen steelmaking (BOS) process, which at that time, over half of the world's steel plants did.

In the latter stages of the steelworks (2003–2012), some of the scrap was sourced from areas out of the south-east such as Crossley's at Shipley and Thomson's scrapyard in Stockton-on-Tees.

[9] The 1980s were an unsettled period for the steel industry and the Co-Steel management implemented changes to working practices and also persuaded all employees to become salaried staff as part of the company with a medical plan.

[15][note 2][16] In 2003, Thamesteel, a Saudi Arabian backed company, reopened the plant to produce steel billet and export it to the Middle-East.