TO GO WITH AFP STORY BY SEBASTIAN SMITH (FILES) A file photo taken 21 December 1999 shows visitors admiring, in Rome, "La Danse" ("The Dance"), by French painter Matisse, at an exhibition of 1,000 famous works of modern art from the Hermitage Museum in St Petersburg. Moscow cancelled a London exhibition of French and Russian masterpieces 20 December 2007, saying Britain had failed to guarantee their safe return in the latest diplomatic row between the two countries. Britain failed to persuade Russia to loan the 120 works by French and Russian painters, including Matisse's "The Dance", said the head of the Federal Agency for Culture and Cinematography, Mikhail Shvydkoi. AFP PHOTO / GABRIEL BOUYS (Photo credit should read GABRIEL BOUYS/AFP/Getty Images)