Time is running out to preserve historic wall paintings around England that are at risk of deterioration and decay, English Heritage has warned.
The charity looks after 77 of the paintings, many of which decorate medieval abbeys, priories and churches.
It said the damp British climate and flawed restoration attempts threatened the artworks, some of which were older than the Sistine Chapel.
In an appeal, it said: “We need the public’s help, before time runs out.”
Paintings under threat included work at Lullingstone Roman Villa in Eynsford, Kent, and a Victorian gothic decoration at St Mary’s Church in the grounds of Studley Royal Park in North Yorkshire.
Many depicted religious scenes, including the “internationally-important” art at St Mary’s Church in Kempley, Gloucestershire, the charity said.
Unlike paintings in France and Italy that benefited from a warmer climate, England’s damp weather could damage the fragile works.
The fact they were fixed to a wall also meant they could not be moved to a suitable place to preserve them.
Meanwhile, early 20th Century attempts at restoration had caused “more harm than good”, English Heritage said.
Those practices included the use of soluble nylon to prevent damage, which had caused increased flaking of paint, it explained.
An audit to assess the deterioration had begun as had urgent work on those most at risk, it added.
These included medieval paintings at Longthorpe Tower in Peterborough, World War One graffiti at Richmond Castle in North Yorkshire, and the Archer Pavilion roof at Wrest Park in Bedfordshire, which needed securing.
Conservation work included examining layers of paint with imaging techniques and undoing outdated methods of preservation.
Launching its appeal, the English Heritage’s senior collections conservator Rachel Turnbull said: “Wall paintings are the most challenging type of art to care for but they offer a precious insight into England’s story.
“People of the past have left little traces, glimpses into their everyday lives through richly decorated wall paintings.
“If they are to survive for future generations to enjoy, we need the public’s help today to repair their buildings, stabilise their structures and protect them from damp and decay before time runs out.”