Built for Richard Thomas & Baldwins Ltd, the works was originally referred to locally as "The RTB", before being called Spencer Works and later Llanwern under British Steel. The steelworks is situated alongside the South Wales Main Line east of Newport, offering excellent rail transport for the works.
Steel making at the site ceased in 2001 with the loss of 1300 jobs, and the 'heavy end' of the works was demolished in 2004. In January 2009, Corus announced that it was mothballing the hot strip mill, with the loss of over 500 jobs. In August 2009 Corus announced that the hot strip mill would resume operations. Subsequent problems caused by the eurozone crisis forced the company to once again mothball the Hot Strip Mill commencing 24 November 2011 with plans to re-open during late 2012. This stance was released to the press on December 2, 2011.
While the site no longer manufactures steel, Tata's remaining operations at Llanwern include a hot strip mill, two pickle lines, a cold strip mill and a hot dip galvanising line. The works rolls 1.5 million tonnes of steel coil per annum for automotive, construction and general engineering applications. 
A £115m renewal project called Glan Llyn, led by St. Modwen Properties PLC, is currently transforming the former steel-producing part of the Llanwern steelworks site. Started in 2004, the masterplan envisages 1.5m sq ft of employment-generating accommodation hosting 6,000 jobs, 4,000 new dwellings, community facilities and open space including 3 new lakes. Full completion is anticipated by 2026-8.
- The Welsh Academy Encyclopedia of Wales, University of Wales Press, 2008
- Aylen, J. (2004). "Megabytes for metals: Development of computer applications in the iron and steel industry". Ironmaking & Steelmaking (Institute of Materials, Minerals and Mining / Maney Publishing) 31 (6): 465–478. doi:10.1179/030192304225019324. ISSN 0301-9233.
- Aylen, J., Natural experiments in innovation: radical adoption of computers and changes to physical and social technologies at Llanwern steelworks, South Wales[dead link]
- South Wales Argus, September 2004 Missing or empty
- "Fears for over 1,100 Welsh steel jobs", new.bbc.co.uk, 26 January 2009
- "Llanwern steel mill to go back to work", www.southwalesargus.co.uk, 20 August 2009
- "Tata Steel to mothball hot strip mill at Llanwern, Newport", www.bbc.co.uk, 2 December 2011
- "Tata Steel : About us", www.tatasteeleurope.com, Llanwern works, retrieved September 2012
- Jost, H. P. (1964). "The planning and organization of lubrication for a new integrated iron and steel works". Proceedings of the Institution of Mechanical Engineers, Conference Proceedings 1964-1970 (vols 178-184) 179 (1964): 287. doi:10.1243/PIME_CONF_1964_179_090_02. , includes description of works c.1964
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