LONDON — Britain’s National Portrait Gallery said Tuesday that it was not accepting a long-discussed $1.3 million donation from a charitable arm of the Sackler family.

The decision, reached by mutual agreement between the gallery and the Britain-based Sackler Trust, is the latest sign of the changing climate in the art world toward the family, which has links to the opioid crisis. Members of the family own Purdue Pharma, which makes OxyContin.

“The allegations against family members are vigorously denied, but to avoid being a distraction for the National Portrait Gallery, we have decided not to proceed at this time with the donation,” the Sackler Trust said in a statement.

“We understand and support their decision not to proceed at this time with the donation,” David Ross, the National Portrait Gallery’s chairman, said in a statement.

The Gallery had been considering the gift for over a year, as the controversy around the Sackler family has grown. Nan Goldin, the photographer and anti-opioid activist, drew attention to it last month when she revealed she was in discussions with the gallery over a retrospective. “I have told them I would not do it if they take the Sackler money,” she told The Observer.

The gallery has an ethics advisory committee that provides advice on whether to accept donations. It met shortly after Ms. Goldin’s comments, according to The Art Newspaper. Its advice was confidential and will not be released, a spokeswoman for the National Portrait Gallery said in an email.