The curators were powerless to stop them, even though the triptych (above) has been in their museum since 1977 because the owners, St Paul's Church in Brighton, have decided to sell it. When it is auctioned in November, it is expected to fetch between pounds 350,000 and pounds 500,000.
The sale is a last resort for the church that needs pounds 1.7m to save its Grade II listed 1840s building with a spire that is a Brighton landmark. Engineers estimate that within two years, the 150ft tower, which suffered severe damage in the 1987 hurricane, will fall or have to be demolished. At the moment, it is shrouded in scaffolding to protect passers-by.
A Sotheby's spokesman said the church had for years agonised over the sale, exploring every possible way to avoid it, 'even to the point of selling the land on which the vicarage is sited. There was simply no other means of raising the money.' The altarpiece, commissioned for St Paul's in 1861, was loaned to the museum when the church authorities could no longer accept responsibility for it because insurance costs had become too high.
Andrew Barlow, Keeper of Fine Art at the Brighton Museum and Art Gallery, said: 'Although the museum recognises the Church's financial difficulties, it strongly opposes the sale of such a significant work.'