When Helle Thorning-Schmidt, the Danish prime minister, took a photograph of herself with Barack Obama and Cameron at the Nelson Mandela memorial service last week, many thought the move was in bad taste.
But now it appears that Cameron has intervened to ensure the picture is preserved for posterity.
Thorning-Schmidt was so embarrassed by the furore that she secretly pledged to destroy the image. But Cameron has pleaded with her to auction it for charity.
During a private conversation last week, Cameron suggested to Thorning-Schmidt that it could raise a substantial sum.