Seventy-eight artists, including five winners of the Turner Prize, have signed a letter calling on the National Portrait Gallery (NPG) in London to end its sponsorship agreement with energy giant BP. The oil company has sponsored the NPG’s annual Portrait Award for three decades, but the museum has come under mounting pressure in recent years to sever ties with BP amid allegations that the partnership helps the company “artwash” its activities and their impact on climate change.

In the letter, the artist signatories—a list of luminaries that includes Antony Gormley, Anish Kapoor, Sarah Lucas, Christian Marclay, Cornelia Parker, Gavin Turk, Mark Wallinger, Gillian Wearing, and Rachel Whiteread—urged the NPG to end its funding agreement with BP when it’s up for renewal in 2022, find a new sponsor for the Portrait Award, and immediately remove the BP representative who sits on the award’s judging panel. They wrote:

BP’s continued sponsorship of the Portrait Award is lending credence to the company’s misleading assurance that it’s doing all it can [to support renewable energy], and so we, as artists, feel we must speak up.

A crucial role of art is to describe to future generations what it is to be alive now, and to provide an echo of our humanity to those who seek it in the future. The ethical red lines regarding art sponsorship are always shifting, tracing the curve of corporate behaviour and what’s regarded as the public good. This was clearly demonstrated when the NPG moved away from its partnership with tobacco company John Player thirty years ago, and the Sackler family earlier this year.

While Tate opted to end its sponsorship agreement with BP following years of protests, major U.K. cultural organizations including the Royal Shakespeare Company and British Museum have kept the company as a sponsor. At a press briefing on Monday, the director of the British Museum, Hartwig Fischer, described BP’s support as “vital” and said the company will continue to sponsor its programming, according to a report by The Art Newspaper.