A major London exhibition of French and Russian art has been halted over claims by the Russian authorities that Britain has failed to guarantee the paintings' return.
Russia fears that some of the 120 works of art, which include this painting by Paul Gaugin, could be seized to settle private legal claims related to the paintings.
Some of the paintings were taken from private collections after the 1917 Russian revolution.
The exhibition, called From Russia: French and Russian Master Paintings, is currently on display in Dusseldorf, Germany.
Many of the works had not been seen outside Russia before the touring exhibition began.
Gordon Brown and Vladimir Putin were due to attend the opening of the hotly anticipated show at London's Royal Academy of Arts, in January.