The church of St Michael and All Angels, Berwick, is celebrated for its murals painted by the Bloomsbury Group artists, Duncan Grant, and Vanessa and Quentin Bell. Commissioned in 1941, their work was championed by luminaries such as Sir Kenneth Clark as a bold experiment to revive the participation of prominent modern artists in ecclesiastical painting. Sir Nicholas Serota, Chair of Arts Council England, recently described the scheme as “of national and even international importance”.
 
Deterioration of the paintings has been a recurrent concern, which a number of treatment interventions not only failed to remedy but also exacerbated. In 2018 Berwick church began a major conservation project with funding from the National Lottery Heritage Fund and other sources. Environmental monitoring was carried out to determine causes of deterioration, and improvements were made to the fabric and heating system to address these concerns. Rickerby and Shekede were commissioned to treat the paintings. In 2019, they investigated their technology, and the nature and impact of coatings applied to them in the 1960s and 1990s, in order to establish safe treatment parameters. The coatings were problematic for a number of reasons. They left the paintings with a glossy appearance, whereas the artists’ intention was for a matte finish. The materials used had darkened, attracted dirt, and encouraged microbiological growth. Their continuing degradation was contributing to new paint flaking.
 
Over a 3-month period in 2020, cleaning was done not just to improve the appearance of the paintings, but also to ensure their future safety. There were considerable challenges. Each artist executed his or her painting differently, using differing materials and techniques. The paintings had been treated differently in the past, too. These circumstances meant that cleaning procedures had to be adapted and modified continually. Painting techniques, conditions, and cleaning outcomes were assessed using portable microscopy and multi-spectral imaging.