This chart shows whether Sergei Ivanov’s total sales are going up, and if so, whether this is because more artworks by the artist have been offered and sold or because more high-value artworks have ...

Russian artist Sergei Ivanov, 55, vanished from his home on the Orkney island of Papa Westray on April 3. A major air, land and sea search has so far failed to find any trace of him. We told you ...