The brick kiln, chimney, drying sheds, boiler and engine house at Bursledon Brickworks, in Swanwick, are the latest buildings to be added to the annual study by Historic England.
The register is the yearly health-check of England’s most valued historic places and those most at risk of being lost forever as a result of neglect, decay or inappropriate development.
The steam-driven brickworks complex was in use from the 19th century until the 1970s, with what is thought to be the earliest surviving Staffordshire-type continuous kiln with ten chambers.
Now a museum, the buildings of the Grade II-listed site are mainly constructed of red brick, with corrugated sheet roofs.
A spokeswoman for Historic England said: ‘The buildings are at risk due to the vulnerability of the roofless drying sheds’ unsupported walls, and due to the leaking roof above the brick kiln.
‘The National Lottery Heritage Fund has grant-aided a development phase for repairing and converting the drying sheds but funding is required to implement the scheme.’
The site is one of 15 in the south east that have been added to the register because of concerns about their condition.
However, despite the blow, Historic England has insisted that some 20 other sites have been removed from the at-risk register following extensive work.
Among them includes E magazine and enclosing walls, at Priddy’s Hard in Gosport.
The Grade II-listed scheduled monument had been at risk of being lost forever.
However, it has since been repaired and converted into a micro-brewery and bar owned by the Monkey Powder Brewing Company. It opened in May.
Reacting to the number of historic sites saved this year, heritage minister Nigel Huddleston said: ‘I'm delighted that so many famous landmarks have been removed from the heritage at risk register in 2021.
‘We've supported the sector throughout the pandemic with our unprecedented culture recovery fund and it is great news to see this investment, along with other financial support, having such a positive impact.’