THE sale of Picasso's 1932 painting Nude, Green Leaves and Bust for a new world record price of £70m is a tragedy. Unless it turns out that the anonymous purchaser is a public museum — almost certainly not the case — what has happened here is a theft of world culture, art history and beauty from we, the people, by the super-rich.

One of the last great surprises of 20th-century art has come and gone, photographed in the sale room on its journey from one private collection to another. If it appears in exhibitions in the future that will be the result of curators fawning to some billionaire for a peep at what, in reality, should be the cultural property of us all.

Public museums are miracles of redistribution. At London's Tate Modern anyone can walk in off the street and contemplate, for free, Picasso's great painting Three Dancers or Matisse's sublime cut-out The Snail. These works are as valuable, or more valuable, than the painting sold this week — but I can stand as close to them as any oligarch ever will. Andy Warhol said he loved hot dogs because even the Queen of England can't get a better one than the bum on the corner. At the National Gallery in London, the Queen of England can't get a better view of Leonardo da Vinci's Burlington Cartoon than me or you.

The very qualities that make this particular painting so valuable are also the reasons its private acquisition for a price beyond any museum's purse is so depressing. It is a prime work by the supreme artist of the past three centuries (if you share my belief that Picasso was the greatest since Rembrandt). Picasso is the kind of universal spirit whose art seems to transcend time — paradoxically, a timeless modernist. Just look at how the display in 2009 of a tapestry of his pacifist masterpiece Guernica at the Whitechapel Gallery, London, captured imaginations.

— The Guardian, London