The Daily Telegraph’s Sean Rayment reports that Lord John Sainsbury has made a £25 million ($38.6 million) donation to the British Museum. The gift will help fund an extension to the London museum’s exhibitions and ensure the preservation of rare artifacts.

A spokeswoman for the museum said the donation was “incredibly generous” and discussions had been ongoing for a “long period of time.” The spokeswoman said donations from other private donors, plus a government grant, were also being used to fund the project. The gift from Sainsbury, the former chairman of a supermarket chain, comes at a time when many cultural organizations are facing a funding squeeze amid financial cutbacks.

The Sunday Times reported Sainsbury’s gift was the biggest to the arts in Britain since philanthropist Sir Paul Getty pledged £50 million to the National Gallery and £40 million to the British Film Institute in 1985.