Some of Russia`s greatest modern masterpieces are to be shown in London after Moscow was persuaded to lift a two-year embargo on lending its artwork to the UK. The Royal Academy is borrowing 120 paintings, mostly French 19th and early 20th century works by the likes of Gauguin, Renoir and Van Gogh. Many were appropriated from private collectors after the Communist Revolution in 1917. Moscow has been concerned that showing the works abroad gave the collectors` descendents a chance to try to reclaim them, and it stopped loans to countries which did not have anti-seizure laws. Such legislation is now going through Parliament, though it is not expected to be given Royal Assent before the exhibition from January to April next year. However, the academy announced yesterday that it had asked James Purnell, the Culture Secretary, to send "a letter of comfort" to the Russian authorities to say that, until the law comes in, the Government will use its best endeavours to prevent any legal attempts to use the paintings as hostages. The star attraction is Matisse`s The Dance, which has not been seen in Britain before. It was commissioned by the collector Sergei Shchukin. Momentarily, he cancelled the commission, because he was worried about the reaction to the work. He then changed his mind, sending a telegram to the artist saying: "You are a very brave painter and I am a very brave collector."